Sam2, what you wrote is outrageous! That Gemorah never meant that we should not accept Geirim. Look in the last 2 lines in Reb Daniel’s post. I do agree with him.
PBA, I have never seen a weird Ger and I’ve seen a fair amount of them. Plus, as Mamele pointed out “weird” does not equal “insincere” or “bad”. I do not know if there is a high rate of them lapsing, but whatever cases there are they probably, at least, in part caused by the way they are treated.