The way I see it (especially since regsitrations are "pls let me in") .art is admin's house.
If they ask you not to wear shoes inside, you either abide or leave. Petty or not, that's the rule.
If they catch you or your friends with shoes inside, you and your friends are getting kicked out, since everybody else is barefoot/eating off the floor.
There's really nothing weird, petty or childish. You get a warning (suspension?) if you don't fix the problem, you get defederated.
"bUt mUh frEey speyCh" doesn't work in a super-protective, highly moderated "safe space".