Off the Mark
The problem with this argument is that it doesn't lead anywhere. If the Democrats did something in 1983 that you keep bringing up, you have two choices: a) you can agree with their conduct, or b) you can disagree with their conduct. Obviously, the Republicans disagree with the decision to go soft on Gerry Studds, so they certainly can't be advocating the same treatment for Foley.
They may manage to score hypocrisy points against the Democrats (or at least the ones who were in Congress in 1983), but they can't in any way use this to justify letting Foley off the hook unless they actually agree with the original outcome, which, if they did, they wouldn't be bringing it up as an example of hypocrisy in the first place.
So, it's just an attempt to change the subject. The issue of what we should do about this situation is left behind in a confusion of smoke and mirrors. Even if we were wrong in the past, that doesn't mean we should be wrong now, unless Republicans don't really care about anything but the party.
If you think Foley did nothing wrong, then say it and say it loud! If not, then it makes no difference if you're opponents are hypocrites. Keep up this line of argument and you'll just end up as hypocrites, too. And so the world of Washington turns...