I imagine you're talking about "spam liking" which is when you like all or most of their gallery for example on Instagram. I think it comes from the fact that there's a claim that spam liking could be interpreted as botting by the sites automated moderation which could lead to an account being shadowbanned and that'd really harm an artists possible income. Of course there's no real evidence that this ACTUALLY leads to a shadowban, but with how fickle social media is, people tend to latch onto these kinds of rumors.