Reasons why someone might seriously utter this phrase:
1) They were one of the guys, and they fancied the other.
2) They were a friend
of one or both
of the guys, and were pleased to see the blossom
3) Strange to relate, some women like to see men kissing. It's not as common as the reverse phenomenon
, but it's definitely there.
4) The rest of the night
The original WU here was a so-called parody, referring to the highlight of my night was two girls kissing
, but it got nuked. Juliet's superior work rules the day.