It’s exactly what you’re doing, you… marine mammal! [I’m joking.]

Serious now, this Wikipedia page has an amazing definition:

Rhetorically, sealioning fuses persistent questioning—often about basic information, information easily found elsewhere, or unrelated or tangential points—with a loudly-insisted-upon commitment to reasonable debate. It disguises itself as a sincere attempt to learn and communicate. Sealioning thus works both to exhaust a target’s patience, attention, and communicative effort, and to portray the target as unreasonable. While the questions of the “sea lion” may seem innocent, they’re intended maliciously and have harmful consequences.

So it’s basically “I’ll keep trying to engage you in a debate, because eventually you’ll lose patience and shut up”.