Telescopes and particle accelerators have their good scientific purposes; looking for ET is not one of them.
There are a lot of reasons to study planetary atmospheres having nothing to do with ET.
Now... If an enterprising young SETI researcher wants to look at that data with something else in mind, I’m assuming you’d be okay with that? We could study exo-atmospheres for what you would call legitimate scientific reasons, while giving those scientists interested in ET a way to pursue that line of inquiry. Two birds with one stone, everyone’s happy.
That’s what I like about FR: Everyone working together to solve what seem to be intractable problems.