There is another reason that is more delicate to mention for SPs which is technique.
Let's not kid ourselves but we are not all gods gift to women when it comes to sexual pleasure. Some are complete morons when blood flow goes to their dicks, "dahh pushhy pushhy, me gonna prime yah". They never take into consideration if the lady is lubricated or not and shove their bit fat DRY fingers up her pussy as if there was no end, then go into a pumping rage that would put the Eveready Easter Bunny to shame to "make her cum".
Of course some will say all she has to do is tell me to slow down but unfortunately when they have to warn us it may already be too late. Women's genital area, like ours, are very sensitive. We can just think how we feel having our glans rubbed by a dry palm non stop or even worse our frenulum as if it were a guitar string. It's the same for women's anatomy.
Add to this that their body is their "work tool", if I may say, that can be hurt from just a few seconds of awkwardness which may even require a few days off in order to heal. For many this is their livelihood, their bread + butter, days off = no income.