Wow, this is ridiculous. I mean, imagine if Twitter or Facebook did this, and started contacting people who liked too many tweets or profile pages. Or if YouTube complained that certain users were liking too many videos. We’d have an uproar online!
Heck, I used to have someone on a site I ran who rated every single post and profile comment on the site. Didn’t think it was odd or something to complain about.
It’s not a problem, and it’s crazy that Medium are treating it like it is one.
Either way, I say you should just continue what you’re doing. Like the posts or responses you enjoy reading, post whatever articles or comments you like and ignore such petty messages. You know you’re a human using the site as it was intended, don’t worry too much about staff that clearly weren’t expecting people to like their platform as much as you do.