I feel like I've been sealioned in the federated instances. It's why I only browse by local/subscribed now, and if I do venture out and talk politics, I cut myself off if the liberalism/reaction is terminal.
I met it in particular with Ukraine. I would explain my view and be met with a question like, 'but don't you agree that Putin is a bad man?' as if the answer or question were relevant. Then I'd clarify my point and get asked another asinine question, perhaps the same question re-phrased in a hundred different ways.
It's the everyday-liberal's filibuster.
I think sealioning can be coupled with moving the goal posts, as the sealion will refuse to understand your point and ask a question that is transparently intended to make you agree with them and admit that you were wrong.
You see a similar thing with Palestine. You can give whatever analysis you like and your interlocutor will repeatedly spam variations of 'Do you condemn Hamas?' It could be a mental block for them. Like they've been trained not to understand that Israel is a genocidal settler colonial apartheid state unless you agree that it's justified in some way (only then can you try to find common ground that genocide might be bad).
Idk. When it's happened, I've maybe given people too much credit. Make they really just don't understand, can't comprehend what I'm saying. I guess it's like this: liberalism stands for unprincipled compromise and liberals naturally sealion until every critic has given up or abandoned their own principles, too.