Ever talked into a walkie-talkie? Hand held Ham radios can transmit as much as 5Watts an inch from your face.
Operators used to measure the base current of AM towers every shift, standing directly under the tower.
We tune AM towers (5kW) standing right at the feed point of the tower, at the base.
Yes, I've worked under TV towers with effective radiated power of a million watts. It is the antenna gain that makes it dangerous.
Yes, we have RFR studies to make sure we aren't spitting massive power into one spot on the ground near the tower. That said, RF power drops very quickly over distance. We can expect more than 30dB loss at 100meters. So, 100W= is less than .1W at 100 meters away.
Are we worried about every Ham running over 100W? Does their license keep their signal clean?
I'd be concerned with a fancy antenna or high power, like 1kW+
As to the technical:
I had to read the post over and over to get the point. I think he's saying that 87.9 is not 70dB lower than 88.3, within the contours of the license. He claims it is only 64dB less. OK, drop to 25W and your signal drops about 6dB, to -70dB under the other carrier.
I'm not sure where he got his numbers. Radios need 70dBV for usable performance but that's a very different topic.