So yes, supporting racial profiling makes you a racist, sorry for that.
You're jumping to conclusions here. There is a huge difference between arbitrary prejudice based on, say, skin color, and very much nonarbitrary one based on one's past experiences with a group. If a correlation between race/ethnicity and, say, violent tendencies exists, then it would be foolish to ignore. This says nothing about whether is's a casual relationship, some sort of common cause or simply bad luck on their part, but the fact that this sort of correlation exists can not be denied.
Think about it, just how do you know that fire is hot and burns? It is precisely because you experienced it. A theoretical physicist might explain
why, but even if you're in the middle of the desert with no scientist in sight, that doesn't change the fact fire burns. A caveman would be clueless as to why, and will not be able to explain it like you did (he could create a myth about it, though). Same thing with racial profiling. You know that Black/Arabs/whoever is dangerous, because you've seen them being dangerous (at least, as far as their districts go). Now, if you're into that kind of thing, you might want to find out
why is that so. There is a very good explanation for why both of those groups are the way they are (I won't delve into psychological portraits here, but it's likely been explained by psychology experts somewhere). It is important to remember that and not attempt one's own explanation, as a myth arising might be very harmful in such situations, and will lead actual racism when people start making predictions based on it.
Of course, as with all "soft" sciences, exceptions are plenty. A well educated Arab student at an Israeli university is unlikely to be actually dangerous to anyone, and in fact will likely be appalled at how the average lower-class Arab acts towards Jews. There's much more to profiling than race. Here, we're mostly talking young, generally lower-class people. In general, in this group, black people are disproportionately represented among criminals. In a similar vein, black people also seem overrepresented in the American lower class in general, which is where most petty criminals come from. As such, when encountering a young black man dressed in a hoodie, I'd definitely be vary of him, even though I don't have anything against black people in general.
This kind of profiling is not entirely unjustified in many cases, but using
only race as a criterion would be racist. Using it alongside other criteria (class, age, sex, etc.) is reasonable. I certainly haven't heard of any incidents involving an old black woman, for example.