Your second sentence is basically exactly the problem: able-bodied people are arbitrarily treated as the “default”, and others are left out.
Able bodied people are the default because they are the absolutely overwhelming majority.
Let's agree to disagree, I think.
Almost everyone develops some disabilities as they age. 10-15% of the population has some disability, which is a huge group. I hope you would not argue for discrimination against ethnic minorities on the same grounds.
That is an absolutely incorrect and indefensible point. Discriminators can be individuals, but discrimination is systemic. It can be a result of collective acts of malice over years or generations, or can be simple ignorance- being left out of the scope of the discourse and never really given a chance to get in the loop.
In any case Cloudflare's inaccessibility is a direct result of choices they "actively" made. Technical decisions, prioritization, maybe even company culture.