I'm using Windows XP, why isn't voice chat working for me?

From https://support.riotgames.com/hc/en-us/articles/360000809887-Parties-and-Voice-Chat-FAQ: "I'm using Windows XP, why isn't voice chat working for me?

 Because you're using Windows XP. It's older than a lot of players, so go ahead and update your OS."

Then why do you guys still use Microsoft Visual C++ from 2005 and DX 9???? XD