If you know some French, pronounce it the way you know it should be pronounced. If you don't, then learn some.
Then you'd only be a "sound much worse" putting on airs asshole, C.
You completely ignored the reasons and obviously got all upset because you're one of these people who puts on airs.
How do you propose learning the sound system for all the languages from which English has borrowed words? It's ludicrous to suggest that we try such a thing. Have you ever heard a foreigner speak? They sound like foreigners because matching the sound system of other languages isn't something that's easy to do.
Children who are fluent in two languages don't intersperse their English with the sounds of their second language for those words that are borrowed from their second language.
How would they even know they are borrowed? And if they did, it wouldn't matter for they are bright enough to know that they are speaking English.