I agree and put in Bayesian terms it seems to me that the prior for “aliens are here, and are hiding from us, but are hiding badly” should be non-zero but very low.
The kind of evidence we have seen should just our priors upward very slightly, but has too many other (more likely) potential explanations to have a significant impact for me.
However, a self replicating probe might well be monitoring the earth, and watching for various milestones (fire, wheels, radio, spread spectrum, nuclear, fusion, stealth, inter planetary probes, plasma drives, etc). Certainly many things could be monitored passively, but occasional active monitoring might be justified.
Things like pestering military vehicles in relatively crowded seas (Off the coast of San Diego) to see what exactly we do when confronted with a unknown vehicle. What sensors do we use? How sophisticated are they? Do we risk the lives of fellow humans opening up on the unknown with multiple weapons?