Sj
its a matter of honoring the Ribono Shel Olam, when you Daven, know before Whom you are standing.
it’s a matter as well of protocol, and convention. someone surely will say that Hashem doesnt care about externals, only ones heart. but Chazal have taught us that clothing deeply affects ones heart. take a bum off the street, clean him up and put him in a policemans uniform with a badge, and minimal training, and generally he will uphold the law with pride (at least until he becomes corrupted). just tell him that he is obligated to uphold the law and it will be a different story.
you cant stand before the Ribbono Shel Olam in bluejeans, sandals, a t-shirt and baseball cap the same way you stand before him in a dark suit white shirt tie, and formal hat, especially as it conforms to the conventions of the local Yeshiva community {because of how YOU feel}, the Yiddin who understand the need to set ourselves apart from the nations, externally as well as internally, as is expressed throughout Tanach and Oral Law.
someone maybe isnt on that madrega, fine, but dont say that is not the madrega we should all aspire to.