If black people are under-represented in certain sports, is that racist?

Racism remains firmly anchored in the news, to the extent that it's hard to find out what's happening regarding the coronavirus pandemic (in case you weren't sure, hundreds of people are still dying each day, but I guess that's no longer news). And I guess it was in this context that CBC Radio 1 aired a segment looking at black people in cycling (or the lack thereof), and it was reported that the first black participant ever in 108 years of the Tour de France was Guadeloupe cyclist Yohann Gene, who competed in 2011.
Interesting enough, except that the presenter characterized this as just one more example of institutionalized racism (or anti-black racism, as it seems we are now supposed to call it). Which made me wonder: how? why? In what way is the fact that not many black people have taken up competitive cycling an egregious instance of racism? Were they prevented from taking up the sport? They may well have been made unwelcome in private cycling clubs up until a certain date (I don't know - the 80s?). But I think it's probably just not a sport that most black people have ever had much interest in until relatively recently.
Blacks are hugely OVER-represented in certain sports like basketball and American football, and distinctly under-represented in other sports like hockey. And, apparently, cycling. Latinos are over-represented in baseball, blacks and Latinos ate probably slightly over-represented in soccer, and maybe under-represented in tennis until recent decades (and possibly over-represented now). People of Afro-Caribbean heritage are over-represented in sprinting athletics events, while the small subset of East African excel at long-distance running. It gets conplicated.
You could go on and on in this vein if you thought it was profitable. But I think that some races are over-represented or under-represented in some sports for a variety of different reasons, from physique to culture to weather to wealth and poverty. It doesn't necessarily have to be fuelled by racism, although in some cases it might be. It's similar in many other fields of endeavour: what is the significance of the fact that there are relatively few black theatre actors and opera singers (although that too is changing rapidly in recent years), but they are hugely over-represented in hip-hop and rap (which is where all the money is in pop music)? Etc, etc.
Anyway, I meander. My point is, I am not in complete denial that racism exists, à la Trump administration or Doug Ford or François Legault, but I just think that people need to be a bit more careful about how they use the "R-word", lest it lose its power through overuse. It should not just be used as
an easy way to shut down a conversation or debate, and there is no particular merit in a white person invoking or admitting to racism if they do not have good evidence of it and/or a viable solution to put on its place. It is not something that should be talked about or mentioned just because it is expected - that would come under the heading of "virtue signalling".