Agreed, but it works for some.The term SPH is really a poor one.
I used to feel that way. When my marriage was going down the toilet and my wife was fucking around, I used to sit at home and imagine what might be happening (she never told) and fetishised it, I was the cuck with the small cock, she was out getting smashed by men with horse cocks and lovoing every second of it. Hey, I wasn't getting any and you have to get your thrills wher you can, right?...seeing a cock that is twice the size of mine fills me with a sense of inadequacy that I find is quite stimulating. Whether that is fetishing or not, it certainly excites me and I am sure scores of other guys with smaller than average cock sizes.
I'm mentally in a whole different place with a lover I know I can trust 100% (She soesn't have to cheat, she can fuck anyone she wants). She actually gets off on having me involved, usually in a 3some, occasionally I'll watch and claim her after, but I have no insecurities about the relative size of cocks. I love seeing her with big ones, visually it's a buzz, but I don't fetishise it or feel humiliated by it.