Personally, i consider this bad advice. Fighting is never really a good thing. SO please don't start a civil war, all it will do is destroy the company. The whole vengeance thing is very counter productive. I'd say lawyer up to get compensation and not to take revenge. And then leave and find a place where you are more appreciated. perhaps focus your energies on something new , something productive
It depends. Is company worth fighting for? What would be your share if you keep your part of the slice? If that is bigger than compensation you would get, than it certainly is worth fighting for. It's not about vengeance, it's about founders own interests, even if that would make company worse off.
45% share of 100M$ worth company is still much more than 10% share of 200M$ worth company or 1M$ compensation. You are not fighting to optimize for the company success, you are fighting to optimize your own wealth. If the company gets destroyed, and you still manage to get more then what would be your compensation package, you are still better off then retreating. Why caring about the company that doesn't benefit you, you would certainly not enjoy the success of the company that squeezed you out.
So yes, lawyer up and fight if it's worth to you to fight for the control. Don't be emotional about he company and business. It's your weakness, and they are already playing on that.
Well as someone here pointed out, the whole fighting thing is toxic. It even marks YOU for the rest of your career. You can't just go to everyone and say "he started it!". outsiders would see BOTH of you as dangerous, and would likely avoid working with you. So it's more of a suicide mission really