Sealioning is the name given to a specific, pervasive form of aggressive cluelessness, that masquerades as a sincere desire to understand.

A Sealion is a person who, when confronted with a fact that they don't care to acknowledge, say, the persistence of systemic racism in America, will ask endlessly for "proof" and insist that it is the other person's job to stop everything they are doing and address the issue to their satisfaction.

The name "Sealioning" comes from a most splendid webcomic,* Wondermark, by David Malki. #1062; The Terrible Sea Lion

Notice the key elements:

Pervasiveness - Sealions don't go away.

Pretense to politeness and sincerity - Sealions are just "asking nicely" but they are asking questions that have been asked and answered fully many times, and are unwilling to so much as open a tab to look up the answer, nor will they recognize the validity of your sources, your experience or expertise.

But, really, they just want to know.

As I wrote in a conversation elsewhere:

Sealioning is not predicated upon any implicit understanding of public/private space, but upon the premise that the asker is "sincere" and therefore all resources possible *must* be immediately diverted to teaching them, immediately. The resources that they could, with minimal effort find, are not the issue. They demand attention - your attention. All of it. RIGHT NOW. And they have no intention of listening, because it's your job to make them understand. It is a specific form of harassment. You may not look away, or point them to a link. You must spend all your time and energy. This isn't a sincere attempt at anythinging. It's a calculated technique to grind an opponent down.

* Not sarcasm. I am a huge fan of Wondermark and have been for many years. I have a sticker from them that reads:

I love it with all my love.