How is the integrity of elections affected by Russians doing things that are legal?

Their crimes were mostly hiding their identities and committing wire fraud.

It is not illegal to discuss politics, or institute a campaign against or for a candidate, on the internet.

It is not illegal to hold rallies, for or against a candidate (or both).

So just how was the sanctity of the election affected?

If these people committed crimes, lock them up, but spare me the histrionics about election integrity.

Candidates spend millions and billions of dollars doing the same things these people did.