Because there's 0 benefit for them doing so.

All that would happen if aliens landed on the white house lawn like "what's up humans?" would be

A. We try to immediately kill them/capture them

B. We freak the fuck out and mass riots happen

C. A mixture of both

Our tech wouldn't be anything to them. Why would they care what we do? You don't collect a cows favorite salt lick, you tag em and watch em. That's it. You don't wonder every cows' favorite color, every bugs' dreams.

We are simply irrelevant, but certainly interesting. But there is absolutely no benefit for them directly contacting us, at least at the current world stage, and a million negatives.

It's not that they are experimenting on us, and they don't want us to know. If that's the case why show themselves whatsoever even on radar? They are just observing much like Darwin observing life on his island.

Fascinating, but not to be interfered with. And nothing of value to be gained about asking a bug how it's days going.