I don't know where you got the idea that I though sex is sinful. I only suggested that as a society "responsible" sex (sex that doesn't cause unwanted pregnancies nor get you sick with an STD) is a desirable outcome for society and people in general. Otherwise have any kind of sex you want with whoever you want.

The point is only that sexual media has an arguably negative influence on society and violent media does not so it's not irrational to find violent media non-problematic and sexual media to be problematic for kids.

The 10 year old can see porn and sex has plummeted does not mean seeing more porn = less sex. The world is complicated and there are plenty of other reasons there is less sex happening (assuming there actually is less sex happening)

As just one example, many people claim the reason there is less sex is people stay home and entertain themselves with the facebook/instragram/tiktok/youtube/twitter/reddit/video-games/netflix vs go out and socialize IRL. That could easily be the major factor in decline in sexual activity even if sexual media by itself influences kids to be more promiscuous.