In light of the replies and observations others have posted, I’d say, yes, the sea lion comic illustrates a type of annoying behavior very effectively.
My reactions, as detailed in the OP, are the reactions of someone on a message board where “sealioning” is being discussed as an inappropriate behavior on the board. And it was in light of that consideration that I said the sea lion comic does not do a very good job of illustrating the problem, meaning the problem of sealioning on a message board. There are behaviors that are reasonable for a pair of humans walking along the beach that aren’t so reasonable for a person posting an opinion on a message board.
On message boards, including SDMB, we’ve famously seen people sealioned for some damn innocuous initial opinions or tastes. It’s happened to me here, in fact. But we’ve also seen people make statements that were incendiary and then act like they were being harassed when people asked for a cite or to unpack or defend what they’d asserted.