Many people in EA value personal productivity highly, and make it a goal to complete as many tasks on their to-do list as possible in a day. Some people (myself included, in the past) seem to tie up their feeling of self-worth with how productive they felt that day.
I think that increased productivity should mainly be used to reduce the amount of time we work each day, and not to get more things done. To live a truly fulfilled life we need more unstructured, unproductive time when we can be ourselves and do the things that we find inherently valuable and enjoyable.
Here are some things that I find valuable in themselves, and not particularly productive:
Running along a river or canal in the morning
Reading a history book in a café
Listen to classical music on the radio
Prepare an elaborate dinner for my girlfriend
Try all the different types of cheese from my local shop
I don't think this position is unpopular in the EA community. You have more than one goal and that's fine got lots of upvotes, and my impression is that there's a general consensus that breaks are important and that burnout is a real risk (even though people might not always act according to that consensus).
I'd guess that it's getting downvotes because it doesn't really explain why we should be less productive: it just stakes out the position. In my opinion, it would have been more useful if it, for example, presented evidence showing that unproductive time is useful for living a fulfilled life, or presented an argument for why living a fulfilled life is important even for your altruistic values (which Jakob does more of in the comments).
Meta meta note: In general, it seems kind of uncooperative to assume that people need more of things they downvote.