Well, he did make sexual comments to the man when he was 17, back in 1997. So that seems fair game to me.
Which is worse: Sexual IM's to a 17 year old page, or having sex with a 17 year old page?
If Gerry Studds were still in Congress, I'd be calling on him to resign as well. But the Democrats of today should not be still held responsible for something that happened in 1983 (not to mention that there was no cover up of those activities by the Democratic leadership at that time).
Although it should be noted also that at least in the case of Studds it was a consenual relationship. The boys that Foley was repeatedly making advances towards were not interested and told him so, and he continued to do it. So from that standpoint, I think there is some blurring of the lines as to which could well be considered worse.