If by "dogpiled", you mean "having your public communication using a hashtag responded to in public by lots of people".

Volume of replies does not harassment make.

>If you criticise them, you will receive rape and death threats.

This is frequently claimed but there's little evidence of it.

This whole thread is just a great example of this comic: http://wondermark.com/1k62/

That comic, in turn, is just another efficient mechanism for evading criticism instead of answering it: as if the number of people making a criticism, whether large or small, has any connection to how valid the critique is. If someone was making racist remarks in a public venue and got a lot of angry pushback, would you dismiss that as "sealioning" too?

A fun exercise: Compare the definition of "sea lioning" with basic conflict resolution tactics. Then, try to explain how they're substantively different.