I’m not sure what you’re stuck on. Just because someone dresses a certain way and calls themselves Frum- doesn’t mean that they’re Frum.
If you see a guy with a hat and jacket driving to shul on Shabbos- would you call him Frum? Would you eat in his house.
If you see a supposedly Shomer Shabbos guy in McDonalds eating a Happy Meal- would you call him Frum?
If you found out that a kollel yungerman is “married” to a male- would you let him learn with your kids?
If you found out that a supposedly Frum neighbor (with long payos and everything) identifies as a female and hangs out in girls locker rooms – would you let your kids into his house to play with his kids?
If you found out that someone in your shul votes Democrat- would you still let him have kibbudim?
So, just because someone dresses a certain way, acts a certain way and claims to be Frum- it doesn’t make them a שומר תורה ומצות.
I’m not sure why you’re surprised by the way they act.