For the record, I'm not an American and I don't microwave water for tea. Being a Brit of these blessed shores, and of our blessed 230v mains electricity supply, I have an electric kettle.

I am also a big tea drinker, and I'm perfectly happy with my setup. I have a metal kettle with a thermostatic heating element (because I prefer my green tea brewed cooler than my black tea), and I use filtered water (because I live in a very hard water area). My kettle is kept sparklingly limescale-free. I am well used to drinking other people's terrible tea, and I know what a good cup tastes like and how to make one.

But I also know that heating water in a pyrex jug in a microwave is exactly the same as heating water in an electric kettle, as long as you're not leaving it boiling for too long or letting it cool too much before using it. Because heat is just heat...