I hope that MILF wasn't
your MILF.
Seriously, though, that seems typical (but not everyone is the same way). Porn doesn't turn me on, but I still love sex. I was worried that I wouldn't since I've always been into tickling.
In psychology, a "paraphila" is defined as something that's required for sexual excitement to the exclusion of genital stimulation. That's more rare than just being really into a material or activity, and having that one thing be what turns you on the most.
As they evolved, our brains increased in complexity by adding layers. Under our mammallian brain we have what's called the "reptilian brain" that drives our basic functions like breathing, hunger, and sex. Most of those behaviors are more complicated (how we obtain and share food, for example, and how we go about selecting sexual partners) but the basic drive comes from deep within. For males, that drive is satisfied (at least temporarily) by orgasm and ejaculation. If you're sufficiently turned on (some people need tickling for that, others don't) physical stimulation of the genitals can bring you to climax.
Porn has to be seen and interpreted by the higher parts of the brain. Physical stimulation doesn't need the same kind of processing. And of course, what's nice to look at and pleasurable to feel are not always the same.