It sucks for everyone sane on the plant if isane guy tries to blow entire world just reach power... i doubt that even sane mages would be happy with it
You can't eat the earth! It's where I keep all my stuff!
But, seriously, the whole "mages cause problems" chain of reasoning is completely worthless for decision-making. Here's a reductio ad absurdum comparison so you can see why:
"People get hungry every day and if they don't get food they can go crazy and riot and stuff! Needing to eat causes SO MANY problems!"
It does, too. But would anyone (who wasn't clearly off their nut) suggest that killing everyone who needs to eat is the solution? No. Or that everyone should be lined up and force-fed to prevent food-related problems? Also no. Focusing on the DAMAGE something causes as its only significant trait and then focusing your efforts entirely around damage control or elimination is useless. It doesn't take into account the total nature of what you're dealing with and all of its aspects, good and bad. Nor will some sort of statistical adding-up of bodies do you any good because of a factor Frederic Bastiat called "that which is seen and that which is not seen". You can't add up all the people who COULD have died but DIDN'T. It's like dealing with security. It's really hard to add up thefts that DIDN'T happen. So, even with a statistical analysis you're comparing numbers to a void. You still don't know what you're dealing with.
This is why you need principles to guide you--principles formed from an enormous breadth of experience not just with one subject but with every part of life that you can observe. Arriving at those principles is an enormous work of philosophical effort, but once you have arrived at them you learn to, say, see the difference between differences of degree (mages are, in some cases, more dangerous than a dude with a sword) and differences in kind (but mages have the same ability to control their magic that a dude with a sword does--or, at least, it appears so). So, ultimately there's no reason to treat a mage any differently than you'd treat an armed man, to demand that the one be locked up to protect you but the other NOT be.
Of course, if a difference in KIND is ever established (which it hasn't been) and it's really demonstrated that mages just flat out don't have a functional method of controlling themselves, that's a different story.