"mine is one of them."
No, it isn't. Prove me otherwise. According to your definition, anyone who has sex other than in a long-term monogamous relationship is promiscuous. Quote where the WP page says something similar.
"What moralistic is that?"
According to the same Wikipedia page you mentioned "The term can carry a moral judgement if viewed in the context of a mainstream social ideal for sexual activity to occur only within exclusive committed relationships." That's exactly the way you used it.
You presume that everyone has specific end goals with sex. Not everyone who has sex with multiple partners is "experimenting". Not everyone wants to "settle down".
"is just an opinion"
There's no contradiction. Expressing opinions is one of the ways that morality reveals itself. The way you have expressed your opinions is judgmental and moralistic.
"promiscuous people have more risc in contracting a SDT ..."
The majority of people have an STD, even those who never have sex. Some STDs can be passed by kissing or sharing a toothbrush. Others require genital contact. I therefore observe that going within 100 meters of other people, or where other people have been, gives more risk in contracting an STD.
My observation is much more valid than yours, for reasons I highlighted earlier. Yours is mostly pointless, because having sex with multiple partners is only one risk factor, and not even the most significant risk factor. You can be completely monogamous and have only had sex with a single partner, and still get an STD from that partner; all the more so if that partner has frequent unsafe sex with a large number of partners.
"I'm not talking about abstinence"
Never said you were. I'm saying that sex positive safe sex education is more effective at improving social outcomes (reducing virus spread, reducing unplanned pregnancy, etc.) than anything which tries to reduce promiscuity. Therefore your observation is not only full of counter-cases but experience shows it can't be used for effective decision making - except by those wishing to enforce a certain morality.
"some how, you feel judged, I wonder why"
That's the second time you've tried to use that derailment tactic. It's an irrelevant ad hominem detail, and you should learn to not use it.