The Feds might have something to say about that:
§ 338.3 Nondiscriminatory advertising.
(a) Any bank which directly or through third parties engages in any form of advertising of any loan for the purpose of purchasing, constructing, improving, repairing, or maintaining a dwelling or any loan secured by a dwelling shall prominently indicate in such advertisement, in a manner appropriate to the advertising medium and format utilized, that the bank makes such loans without regard to race, color, religion, national origin, sex, handicap, or familial status.
And ETC. for all whole host of other nondiscrimination laws...
Nobody's saying Christians won't be served. But the bank is probably in a 100% Muslim district, so the tellers, etc., will try and be as "Islamic" as possible. It's no different than banks that are proud to speak Spanish.
Actually, it is open to everyone. So if you want a Muslim-style mortgage (ie, bank being the owner, you paying rent-to-own monthly payments) I'm sure they'll give you one.
Bank still makes profit, so whatever they wanna call it, it's "interest" in some form or other. There's a return on capital involved one way or the other.
Unless I don't understand this and only time bank gets paid (ie, makes profit) is when the house is sold for higher value.