I think oral sex is "sex" by way of being a sexual activity but don't "count" it in the same category, at least when people ask, because when most people ask, they mean how many penises have I allowed in my pussy. If someone asked something more general, like "how many people have you done sexual things with," I would count them.
But if I perform or receive oral from a guy, or girl, i'm not going to tell my friend "we had sex." I would say I blew him or ate her out or whatever more ACCURATELY described the act. As Kendra said, idk why people insist on blurring the lines and making things more complicated. Why can't being sexual, considered a sex act, and having sex in the name be good enough? It's semantic, and fairly pedantic as well. Not to mention tiresome.
Making a distinction between sex ie piv and oral sense also makes more sense, because people have real life distinctions for them as well, just as we have distinctions for anal. It's not downgrading its significance or legitimacy. I, for one, don't consider it sex. But at the same time, I tend to think it's a lot more personal than sex, at least when I give it. I really don't enjoy going down on somewhat I don't love. I don't enjoy it at all. There are many people who use oral like a "gateway" that they do that may or may not lead to piv or anal. For me, it's usually only done after piv and when the relationship has really gotten going because I refuse to do things I don't feel good about doing. Saying it isn't sex doesn't say it's less than or not real. It simply recognizes that the acts ARE different and that people think of them and engage in them according to different standards and rules, often times for perfectly legitimate personal reasons.