I constantly see this assumption from people who attack left-wing culture. It is a mistake to assume someone supports PC politics out of "virtue signaling" or a desire to be socially accepted. Maybe some people do that, but many don't. Most of the time you won't have proof either way. Don't assume.

It is intellectually lazy to discount the possibility that someone could assess pro-diversity ideas with an open mind and simply find them superior. Regardless of your politics, that's just giving an opposing ideology the respect it deserves.

You don't know if this guy drifted left because of social pressure, and frankly that's a silly and disrespectful thing to assume.