I'm not the guy you're arguing with but this is literally the argument you're making. You're saying that Thunderbird is not necessary. That's an opinion. You likely hold this opinion because you don't use it. If you did use Thunderbird, you may feel differently. If you used Thunderbird and it shut down, you'd feel sad. You'd want them to keep working on it.

I say working on the I-5 freeway is a waste of time, because I've never driven on it. But thousands of other people do. And they probably feel that it's an important road in their lives. It's not a straw man, it's the other side of your argument. You just disagree. That doesn't make it a straw man.