1. We can work on more than one thing at a time and I’d be quite surprised if the original poster didn’t want to do something about those companies, too.

2. For all their many flaws, those industries also provide something of value. If they shut down tomorrow, people would miss having cars, pesticides, fuels, medications, etc. but if every cryptocurrency suddenly halted tomorrow nobody outside of a few speculators would find their daily life any different. That doesn’t mean that those externalities aren’t real and don’t require action but they’re widespread because there is some kind of real value to society and you’d need a transition plan to avoid disrupting a lot of processes.