Pseudo-french anglo pronunciation

One of the things that has left me completely frustrated is what I term "pseudo-french anglo pronunciation." It is the phenomenon whereby anglophones selectively apply the rules of pronunciation of words - primarily names - from foreign languages. For example, take the name Ceccarelli which is Italian. Now, most people would pronounce the initial "Cec" as "check" but not bother with the intonation. People pronounce "Poirier" as "pwaa-ree-aay" (don't get me started on the pronunciation of the "r") but "Laurent" as "lo-rent" and not "Law-ro'n."

Now, I don't mean to be nitpicky. What bothers me is not how others pronounce things; it is their reaction to how I pronounce things. So when it comes to french names, I know how to pronounce them in English without using any of the French pronunciation rules and I know how to pronounce them in French without using any of the English pronunciation rules. But if I pronounce them the former way, everyone thinks me unrefined and if the latter, too uppity. So my dilemma is this... can someone teach me the selective rules of "pseudo-french anglo pronunciation"?