You're right, the 80% figure I read was from a small poll, it seems 75% is the more accurate figure.
That's honesty. You don't "owe me a reply" but replying selectively is dishonest. It's pretending you haven't heard any contrary information, when you have.
Now given the 75 is quite close to 80, I think calling Steam a monopoly in the market of pc video game distribution is quite fair, don't you? The honest thing to do would be to change your mind in the light of what you didn't know before.