Someone has already voiced the reason
I don't have time/energy to comment
The target is a censored echo-chamber that will ban anyone who disagrees (can't vote/show disapproval if you're banned) - example would be .ml communities having moments about how stalinist USSR did nothing wrong.

Anyway, once a post from a community rises sufficiently to pop up on all, it becomes a part of the larger discussion, and voting will shift towards the opinions of the larger fediverse. This is also usually when communities get discovered by more people. If a community doesn't want the engagement of the wider user-base, a closed blog may be more suitable as a forum, or alternatively have an instance w/o downvoting.

When browsing all or new I do so both to break out of my bubble and to vote on content (usually stuff I find interesting).

[–] [email protected] 2 points 3 weeks ago

Yeah, unfortunately it seems that I am in the minority when it comes to how this "should" be used. I genuinely believe that one of the reasons that open platforms are better is because it's not designed to constantly get me engaged. If they are not meant to keep me constantly engaged, then I shouldn't be repeating/missing the behaviors that were learned when using the more addictive platforms. This means:

Browsing by all is a fundamental mistake. No sane person should be trying to drink from the firehose. It doesn't matter that the firehose is "small" compared to the larger networks. If this network is out of interesting content, then either go elsewhere (and maybe share what you find here) or just close the app and move on.
If a community/instance/person is not open to a healthy discussion, it's better to just block/mute/defederate and move on.
If I don't have "time/energy to comment", then just take a break and move on.

This is why you'll never see me commenting on stuff like politics/news. Not only I find these discussions boring beyond belief, I feel like they are completely pointless. These places serve only as a "two minutes hate" type of thing. No amount of voting/commenting/arguing will ever change anyone's minds.