Moral maxims and questions of international law and sovereignty should be applied equally regardless of subject. The US, by it actions, says that intervening in foreign elections is okay, and therefore it is, according to the US, okay for foreign entities to interfere in US elections.

It is only by universally applying principles of law and moral that we can change them, because you never understand why breaching another nation's sovereignty is wrong (even though this is in the UN charter) unless it is done to you.

>because the us helped to overthrow peron it's okay that Russia interfered in the us elections?

It's never OK, because of the US past actions it's hypocritical to get overly upset when it happens to the US unless also accompanied by an effort to stop in the future. If the US deserves untampered elections, the rest of the world does too. Even if it means the new government isn't fond of the US