So... because I would like things referred to by their proper term, you call me juvenile names.
Why don't we call a television an elevator while we're at it?
Let's call a leopard a cougar, or a panther, too, while we're at it.
Language exists for a reason. And things are named for a reason - to distinguish them from other things.
If we refer to Wimbledon, Roland Garros, The Australian Open and The U.S. Open individually as 'Grand Slams', then how will we refer to winning all 4 of these tournaments in one calendar year? Surely, that can't be a 'Grand Slam', too...
And just because some commentators make this error hardly means that it's right.
I am right, and you are wrong here - there can be no arguing that.
So, instead of taking the lazy way out, and writing/saying 'Grand Slam' when you mean only one of the 4 tournaments that make up a Grand Slam, write 'Major', or 'one of the 4 Majors', or something similar.