White people can and do experience racial prejudice in America, but we do not experience institutional racism, which is the working definition of "racism" for the author of the comment you replied to.

> There isn't any institionalized discrimination in the USA any longer. There's a perception of it, but that's largely self reinforced.

Institutional racism is alive and well here; I'm surprised to be the first one to respond to your remarks stating otherwise. There are many, many studies that show a marked disparity between arrest rates, conviction rates, and incarceration rates for whites and blacks in America. This disparity exists virtually across the board and for crimes which we know are committed in equal amounts by both groups of people such as marijuana use (in fact, whites smoke more weed but are still arrested less frequently for it). Regarding employment, there are also plenty of studies which show that job applications with "black-sounding" names get far fewer callbacks than those with "white-sounding" names, regardless of what else is written on the application.

The difference between people judging someone based on race versus all of those other things that you mention is that in the other cases, society has not been shaped so that "haters of feature set X" are pretty exclusively the people in power, so e.g. bald people are not consistently discriminated against at every turn. This is at least in part what is meant by institutional racism: the random person on the street has little effect on anybody[1], but when people with the same attitude have the power to arrest you, to deny you a loan, to make your life difficult in any number of ways, the result is a hostile environment that is supported and maintained by the institutions that house such people and support their discriminatory behavior by tolerating its emergence in their official capacities.

Institutional racism can be difficult for members of the dominant group to acknowledge or even see. I have only started to become attuned to it myself over the past few years, and I still don't have a very sharp or complete picture of it. It is usually far more subtle than calling someone a name or making a disparaging remark: you will be treated with a veneer of politeness as your concerns are summarily dismissed. It's easy for someone from the dominant group to come up with excuses as to why a particular act is not an example of institutional racism instead of giving credence to the collected experiences of those who are on the receiving end[2]. If you are genuinely interested in investigating and understanding the phenomenon, I'd recommend looking at the statistics before talking to people about it for precisely this reason: what seems innocuous in isolation looks more sinister when you begin to understand the scale at which it is happening.

This comment is not going to change anybody's mind, and that's okay. I just didn't want to let that statement stand uncontested any longer than it already has.

[1] Though, really, when the random person on the street becomes many or most random people on the street, the effect can be pretty devastating as well.
[2] Some are of the opinion that this tendency is itself an expression of racism, effectively assuming that the victims are mistaken or lying while the perpetrators are assumed to be innocent. I am not sure if it is a subtle racism or if it is simply hard to put faith in such a vastly different outcome that developed from a familiar situation. Having exhibited this behavior myself on more than one occasion, I'm sort of invested in believing that it is the latter.