Artists and musicians (and sometimes athletes) often use their celebrity status in their chosen field to promote their pet/(arguably important) social cause(s). Indeed, art and music can be directly used to promote such causes (e.g. in a painting, or song). Chess (and other sports) games cannot be used directly to convey such messages (other than that, maybe, greedy materialism of some kind or other doesn't always pay). Moreover, organized chess in particular may lack sufficient popularity for, say, a (otherwise charismatic) world chess champion to champion a cause with noticeable effect - perhaps, sadly, organized chess may never be popular enough, at least in future.

In the past, the 1972 Fischer-Spassky world championship match, itself, sort of championed a social cause (and with momentary wild success for chess at least) - western free society vs. totalitarian communism. Later, the evil empire struck back, when, in the 1978 world championship match, Karpov narrowly defeated the defector Korchnoi. Much later, a retired Kasparov tried, most noticeably with public pleas, to go against Putin's iron grip on Russia, but to little effect (indeed, at one point an unsympathetic woman publicly hit him over the head with a chessboard).

I once was told that many, many years ago, a certain CFC President rejected a large sum of money, to be given to the CFC from a tobacco company - so at least chess officials, in the CFC anyway, privately have had their eye on social cause(s), at least in the past.