One of my college roommates wrote not too long ago about a vivid memory she has of playing Euchre with friends on the dorm floor and hearing one of them say, while relating a story, that someone had "really jewed her down". She's Jewish, and everyone who would have been with her would have been well aware of that fact, so it seems a little odd for someone to have said it completely unconsciously, without thinking twice. I could easily have been one of the people in the room, even one of the people playing Euchre (since we played a LOT of Euchre in MSU) but I'm pretty sure I wasn't the one who said it. I wasn't even familiar with the phrase, and can, with nearly 100% certainty, say that I have never used that particular expression, but if it had been me relating something like that, I could easily have said that someone had "gypped me" and that is as least as racist in origin.
I don't think I knew the origin of the word "gypped" until I was an adult, or at least it didn't really seem to matter, since the word has, to all intents and purposes, unmoored itself from its original association with Roma gypsies in Europe and the perception of them as cheats and swindlers. Except, of course, if you ARE Roma, in which case, it's still just as insulting as it was originally intended to be. The point being that there are plenty of ways to say that someone tricked you into lowering your price or scammed you out of money without referring to either their race or their religion.
Many words and phrases enter the language and stick because they fill a gap that was missing or they stick because they are catchier or more descriptive in some way. English is notorious for collecting words from all over the place. Wikipedia even has a whole SECTION that lists all the words in English that have a foreign origin (or at least many, many, many of them). And of course it's not just words from other languages. English is also adept at adapting words for other uses and turning nouns into verbs.
But it's still a bit of an eye-opener to realize that some things we commonly say were very deliberately coined and/or used at the start in a derogatory or racist way. It certainly has made me think twice about some of the words and phrases I often use, like "no can do" and "long time no see"...they sound innocuous to our ears now because they are such a ubiquitous part of our vocabulary, but they weren't at all innocent to begin with. And some terms, like "grandfather clause", for example, work so well for their current purpose that it's hard to figure out what you COULD replace them with nowadays, if you wanted to avoid the past-racist connotations that they are burdened with.
You might be thinking, well, what difference does that make NOW? The meanings of many of the words HAVE changed and mostly, I would think, these words and phrases are no longer used in a derogatory way at all. Especially when you DON'T know the origins. They aren't being used in a way that demeans anyone anymore, right? What's wrong with greeting someone with "Oh my god, long time no see!", after all? Well, on the one hand, nothing's inherently wrong with it, but that doesn't make it right. Especially once you DO know. Then, I think, if you continue to use it, you have to make that choice each time, to knowingly use a word or phrase that DOES help to perpetuate stereotypes or disparaging terms or just downright racist language.
If you're interested in doing a bit of cleaning up in the words and phrases you probably use without realizing their dirty past, you can google (there, see?) and educate yourself. For my part, I will be trying to remember NOT to use the the above examples or the following: hip hip (in front of hooray, which will be especially difficult here in Sweden, because it's a standard birthday cheer), uppity, fuzzy wuzzies (not even in regards to the bear), and chop chop. There are plenty of other words and phrases that have racist, derogatory or anti-semitic origins but since I already DON'T use them, I'm not listing them here.
After all, English is a rich enough language that I can find other ways to say all of these things, with a clear conscience.