I suspect I may get more negative comments than you do given that I often write on topics that are more controversial. Even so, I find that Medium is much more positive and supportive than other platforms. I may get a couple negative comments on Medium everyday, but I get dozens or more on Facebook.
I don’t really know why people feel the need to get nasty and personal, but if they do on Medium with me, I simply hide their comment under my story and then probably block them. I have too much to do to take energy hits from naysayers.