Why is it that the people who most demand tolerance and inclusion are the LAST to give it?

If I'm understanding you right (maybe me, and everyone who has read this, unless OP is able to edit/elaborate more etc.] is misunderstanding you, and have no idea what you're talking about) that is simply not true.

Take me for example. I'm Black, autistic, gay, flamboyant etc. I (and I think 99.9999 percent of people in my category, due to the fact, and because we are at the bowels, and at the bottom of the bottom, rust, nautical sea level below the scale etc.) and I include everyone and treat everyone with respect. Even though I don't get the same treatment, but yeah well. Alas.
 
If I'm understanding you right (maybe me, and everyone who has read this, unless OP is able to edit/elaborate more etc.] is misunderstanding you, and have no idea what you're talking about) that is simply not true.
I think he's focused on the 'demanding' side of the coin. Your treatment towards others is of natural behaviour. You do not demand anything, even when you're not treated well, but you treat people well. I think he means someone that demands certain treatment, though do not give in in the same way to others.

I've seen both things happen in many spheres of social interactions. Most of those cannot be discussed here.