I was really talking about fetish, not turn on. If we think a "fetish" is something like a sexual obsession, then probably any fetish wouldn't be normal. But I prefer to separate fetishes due to their specific theme, so if a fetish is for things that belong to ordinary love/sex (as kissing do), I think it's normal afterall and is different from a fetish for something else kinky that I would properly define "paraphilia".
First, I am going to say that fetish is actually a poorly defined word. As you say in a later post, it is overused and it is extended beyond its dictionary meaning often. To make it worse, the goal of a fetish is often defined as "sexual gratification", but "sexual gratification" is another term that is poorly defined. It usually involves an orgasm, but is that always so?
I think of fetish as being a fixation that acts as a trigger for either an orgasm or an emotional/sexual catharsis. So if someone focuses 100% of their attention on an object or a single sexual act and that fixated attention is their orgasm trigger, that starts to feel like a fetish. If a person masturbates to the sight of feet, or ears, or lips, and the visual fixation on this one thing alone is the orgasm trigger, that's clear fetish. It is about an object-like fixation.
So - to Guy's original question - if the person watches makeout videos and that act by itself is the orgasm trigger, I am all-in on calling that a fetish.
On the other hand, if you are simply obsessed with making out and it is part of an overall arousal process - or alternately something you use when you are close to orgasm as a sexual heightener - then I am more likely to think of that as an obsession. But - in common use - many people will call that fetish. There is not well-practiced discipline in understanding what constitutes "fixation" in a fetish.
Now consider the person who fixates on one specific behavior, but they use that to become aroused rather than as an orgasm trigger. I am thinking of masochists as my example. A person who is completely obsessed with masochism might fixate on a very specific behavior - like face-slapping - and they need that specific thing to become fully aroused. But it is not the orgasm trigger. I like your word "paraphilia". But, no one uses a word like paraphilia.
So that is the case where you have a good word selection but probably it is a losing battle to use it in ordinary conversations. People will incorrectly call the masochist who wants face-slapping to become aroused a fetishist.