The sub-8 law refers to systematic legal oppression of non-attractive men (more specifically, men rated below 8 in attractiveness).
Sexual harassment laws exist so that women can have an unattractive man jailed for doing certain approaches that they would find charming if done by an attractive man. This makes it so that an entire class of behaviors that are perfectly acceptable for an attractive man, are unacceptable, even illegal, for an unattractive man.
It is illegal in the United States for a man to pay for a woman to have sex with him. In other words, a man who is not attractive enough to get a woman to have sex with him for free is legally obligated to remain incel. However, it is legal for a man to have sex with a woman as part of a porn film, and it is common for male strippers to get blowjobs from women while stripping. Contrary to popular belief, our society does not prohibit the commodization of sex - it is only when incel males are helped as a result that it becomes a problem.
Why would society actively work to keep incels incel? Because the more incels there are, the more sexual power women have.