Actually, Clinton's parsing was not entirely unreasonable since the term 'to have sex with someone' can have different meanings, and the distinction may be important. For example, if a woman were found to be pregnant, the issue of whether or not she'd had "oral sex" with particular people would not be particularly relevant in ascertaining paternity. Indeed, biblically it would seem that if a woman's hymen was intact on her wedding night her virginity was to be regarded as beyond reproach; that would suggest that a woman who engaged only in 'oral sex' could be regarded as a virgin by such standards (given that a major reason for marrying a virgin was to be sure that one's wife wasn't carrying someone else's child, this again would make sense).
I by no means wish to condone extra-marital relations of such types--merely to point out that Clinton's parsing was not unreasonable. If people meant to ask whether he'd had anything that might be considered 'sexual relations', that's what they should have asked.
I see your point and I could accept Clinton's parsing of language if it wasn't so obviously self serving.
FYI: In the biblical context (or at least in context of the culture of that time) a virgin was simply an unmarried woman. Having not 'known' a man was just assumed.