Yeah, the person with the HMD has a mic, but 99% of the people he can chat with don't have an HMD. Sure, a lot have mics, but a lot don't. The quote you were responding to was about people you meet, not yourself.
In my experience, before I got an HMD, most players preferred to use text chat. I'd ask for a voice channel if I winged up with them, but unless I was with regular wingmates, most didn't want to use voice, or couldn't. But they could receive voicecomms.
And even today, if I watch some ED videos on youtube, it is still mostly text chat except for in regular group wings.
Anyway, the correct answer, as BigDuke6ixx pointed out, is to just send a voicecomms request. Even if they are receive only and still texting themselves, you don't need to be bothered with it.