First-hand experience gives you unique perspective that you can share with others, but doesn't make you a final authority on the matter. Once you shared your information with others (and assuming there's no trust issues involved), you're on equal grounds as to what to conclude from it.
2) One of the things that people keep starting "free speech controversies" over is the idea that some groups are intrinsically less intelligent or apt than others. When, as a member of such a minority group, you are confronted with this idea, what can you conclude from the suggestion that you are intrinsically less intelligent than your classmates?
- the instructor is right, and you should drop out?
- the instructor is prejudiced, so you will receive unfair marks?
- the instructor is wrong about this, and likely to be wrong about everything else?
Do you have any specific examples? I am aware of controversies about some groups being on average more or less intelligent or more or less apt, but that has little to do with a) whether the variance is intrinsic or b) the capacities of any particular individual.
If the instructor is right about variance between groups, why does it follow that an individual should drop out? I wouldn't drop out of school upon hearing that on average Jews and people of Asian-descent are more intelligent than members of my ethnic group -- it is both true and irrelevant to my academic abilities or status, or whether the instructor is bigoted (they may or may not be, but making a true statement isn't evidence either way).
Also, what exactly "intrinsically less intelligent" means? For example, I'm statistically more likely to be less intelligent than people of some ethnic background, but this effect is slight enough so that every time I'm compared to a person from this group (and he has to be randomly chosen, and I have to have no other information about him/her other than his ethnicity for this whole premise to work, btw), it's like 55%/45% in his favour, not 100%/0% - not a reason to drop out either.
EDIT: NB In case it is not clear I personally don't think that there are meaningful e.g. IQ differences between the (in my opinion totally arbitrary) groups of humans that people divide other people into where those groups are based on external characteristics.
Funnily enough when this idea is called "diversity" it's much less popular.