Downvoting is not toxic.
I will admit occasionally I see pretty questionable downvotes, but I never think too much on them. Most, if not the majority, of the time, downvotes are well-justified. People downvote for various reasons: someone is asking a trivial question without showing any research effort or background; the query is irrelevant; the formatting is strange and lacks knowledge of Mathjax/LaTeX; you name it.
To me, it seems like the issue is how you personally handle downvotes. At the risk of being rude, please don't have thin skin and just move on once you realize your mistake. No one on here is trying to offend you. In fact, they are trying to help you by downvoting on what they think is wrong and justifying it in the comments. Once you realize that, then just move on.
I get called out, too. Sometimes I even get downvoted. Me being 23 years old, I imagine I am somewhat younger than most experienced users on this site, so occasionally I get downvoted for having a skeptical answer. But do I take it as hurtful? No, of course not. I read what I did wrong, and either edit or delete my post, depending on how wrong I am. That's all. I've spent my entire life on the internet and gaming an unhealthy amount of years to realize not to take things too seriously.
Also, it is impossible to have "no idea" on how to start a proof. You can at least try something and show it: mention relevant definitions, theorems, corollaries, statements, etc.; do some computational work; link some relevant Wikipedia pages; provide some motivation; at least something. Even if the question is trivial, it is also a good reason to state what your background is. You can look at my questions I have asked on here before for reference, as onerous as they can be.
At the end of the day, you should not be worrying about this ... stuff. You certainly have better things to worry about than seeing a negative number on your computer screen.