Have you ever tried using squirrel-safe feeders? It doesn't work. They're too smart for it.
Do you have any evidence that squirrels visiting bird feeders are is damaging any way? I haven't heard of this before and would love to see any evidence t back it up.
Yes. A close, nearby friend has 5 acres that she's turned into a native species habitat with a bunch of certifications, etc. The squirrel-safe feeders all work fine. She didn't have squirrels until she started using more feeders, and now they've gone back to rarely being seen since they can't get to anything.
There's plenty of links on google, including recommendations from wildlife organizations.