across a variety of modern up/down vote based platforms, some make it a personal mission to avoid downvoting (the only real exceptions when someone is being utterly objectionable, ie. ridiculously racist/sexist etc or blatant spamming (1)
in general, it is almost always better to have a respectful discussion than mindlessly downvoting and moving on. if two parties can meet for respectful discussion the outcome is almost always superior to the text-book divisiveness of a downvote war etc (2).
in a great many cases people usually find they don’t disagree as much as previously thought, have their mind opened to a valuable new perspective, or at worst accept to disagree respectfully. definitely a better outcome.
yes it is time consuming, but don’t we all generally want quality over quantity?
(2) the original idea of a self-moderating community through up/down votes is a good idea, yet appears to have been hijacked by the modern social-media-type weaponised web, which is being turned against humanity to divide and polarize us against eachother. and is particularly suspectible to bot manipulation.
(1) which can have eg. their own flags
I tend to agree with everything you’ve said. The only exceptions being, upvoting can have a positive effect in terms of registering something you see as valuable.
Downvoting I only see as useful if its accompanied by respectful and helpful criticism.