I think it’s different because the MPs are specifically elected by the public to propose (or block) legislation, and the hierarchy of Parliament is in turn dete

I think it’s different because the MPs are specifically elected by the public to propose (or block) legislation, and the hierarchy of Parliament is in turn determined by the votes of same elected officials. The Queen isn’t elected. By the same argument you could say that it’s fine for me to have a veto over British legislation, and I assure you that it would not be.