Restricting democratic positions based on an undemocratic process isn’t good. If a corrupt government wanted to keep someone from being voted out they could just deny security clearances to their political enemies and suddenly the people can’t vote for who they want.
Like others have said, Poilievre could get security clearance if he wanted to. He’s not a foreign agent, he’s just an asshole. He’s currently arguing that those who read the classified documents detailing interference by foreign spies are doing nothing to fix it. He loses that argument if he reads the documents, because now he’s just like everyone else.
This is going to affect hard working Canadians (who make more than $250,000 a year in capital gains)!