Thanks for taking the time to reply! And thanks for acknowledging that it's a good thing to advocate for a ceasefire.

Here is my rationale for it being the best thing:

1. I know it is naive and simplistic to say, but war kills and peace saves lives, no matter the circumstance, parties, or reason for the conflict. If we believe that every human life is valued equally, saving the lives of even the most egregious combatants is worthwhile. 
2. A ceasefire would mitigate further deaths in Palestine, right now. True, protests to end the conflict haven't been effective for three quarters of a century, but I don't understand how it is an argument for not trying to end the acute crisis, while hospitals are being shut down. 
3. Escalation of this conflict is highly possible, in my opinion. I am sorry to repeat this part of the post, but two historically oppressed people are feeling attacked, worldwide. It is hard to play fair when you are feeling attacked, oppressed, downtrodden. It increases the risk of dehumanizing the other side, and illegal war strategies, like chemical weapons, attacks on hospitals and social infrastructure, cutting off supply lines, etc.  Most worrisome, is the people who are feeling oppressed don't just live in Palestine and Israel; the conflict runs the risk of scaling up fast. Hate crimes are already happening in America. The Biden administration is already talking of war. 
4. Regarding time, I am only suggesting you share protests for ceasefire on social media, if you are not doing so already. This takes seconds, considerably less than the time it took you to earn the 20% of your income that you are donating (kudos to you, btw). It takes so little time, I am suggesting you can both advocate for ceasefire in addition to the good you do, without impact on you QoL. 
5. I don't think I am exaggerating when I suggest your efforts could help to save thousand, maybe millions. Not you alone, of course, but as I indicated in my other reply, as part of a movement. I also believe in the ripple effect - if you share your opinion on social media, people who respect and value your opinion may change their mind on the matter, and share calls for a ceasefire to their connections. 
6. If I can summarize, seconds of your time may have both impact for thousands of people in Palestine right now, and advocating for peace might prevent WWIII. It might not, but what is the downside in trying? 

Thanks for your reply; I may be naive, but I think even engaging in the conversation is a start. Even by replying to this post helps it to be seen and considered.

I think that like you, every ‘ordinary person’ downplays their role. Human rights movements, including civil rights, anti-apartheid, and suffrage all happened because of actions of ordinary people. Sure, by yourself you may not have massive influence, but if you share with your social group, your friends and family may pick it up and share with their social group. I agree that time and energy aren’t infinite - I don’t see myself having the time to join one of the street demonstrations, for example, but retweeting pleas for a ceasefire takes seconds.

For what it’s worth, I also take on board the moral force, and feel generally helpless. It is the reason why I am going to these various forums to which I belong, to try and gain traction. Sharing, upvoting, and commenting on this post would also help, as cheesy as the ask may be. Thank you

Is there any sound, rational argument against calling for a ceasefire?

Silence is complicity.

Not engaging in politics only upholds the status quo of structural power. 

Thank you for your reply. I am sorry to hear about your poor personal healthcare experience. 

Regarding your other points:

"Cost-effectiveness doesn't mean only efficiency. I think when you're trying to do the most good, ditching the use of cost-effectiveness is quite hard because what will you use instead?"

Equity. I am suggesting a paradigm shift to considering equity as the most important goal. It means spending more on those less fortunate, but sometimes cost-effectiveness and equity align. For example, Give Well donates to low income countries because it is more cost-effective, but it happens to also be a more equitable choice. The provision of primary health care for all is equitable, and is not  always at odds with cost-effectiveness, see the US spending on healthcare and morbidity and mortality outcomes vs other rich countries which have social health care. The only process by which equity is advanced is through human rights lobby, as far as I can tell.

""Billionaire philanthropy isn't okay, it'd be better if the masses decided what to do" and "Universal healthcare is a moral imperative" are claims which a lot of moral theories would disagree with"

I am interested to see these moral theories.

"A third critique is tractability. Isn't it quite hard to change global political discourse, especially in Africa where most EAs do not have no connection to, and institute health as a global right and actually enforce this? This seems quite unlikely, because this would require increasing state capacity all over the global south, advancement of technologies in underdeveloped countries(if we take veil of ignorance seriously), setting effective and capable health bureucracies in countries where bureucracies tend to be home clientelistic and kleptocratic tendencies rather than effectiveness. Again, I don't think the goal this post propose are actually tractable. This is different distributing bednets."

I agree with this; it highlights the purpose of my post, which is to suggest EAs aim higher in their altruistic goals.

Also this report that big pharma R&D costs are vastly overblown; it is what I had suspected, now upheld by research. 

Strong upvote! I came here to say something similar.  One of your most compelling points is addressing the needs and wants of the intended beneficiaries, in contrast with pursuing the most economically efficient cause area. I think there is significant moral weight in ensuring people have what they want and need, which cannot be commodified. 

Peter Singer has done the math, and it is possible to reduce by half global hunger and extreme poverty, with modest numbers (old article, but I just found it):

https://www.nytimes.com/2006/12/17/magazine/17charity.t.html

While I am here, humbly, I need to ask a burning question: Your advocacy and behaviour are incongruent with respect to consumption; you consume in a degrowth pattern, but advocate for growth, why?