I do agree that if disabled people (or anyone else) experiences discriminatory barriers then those barriers should be addressed rather than condoning sexual exploitation.
I would like to see sex 'neutralised' in our moral environment. While women have been oppressed by rape and sexual violence down the ages, so have women also been oppressed by the moral outrage against women's expression of their own sexuality. Villified for enjoying consensual sex before marriage, cast out for becoming pregnant out of wedlock, 'reputation' ruined for enjoying sex with someone from a non-approved tribal group. A blanket assertion that paid for sex can never represent anything other than a woman being demeaned is to partially play into this moral notion that sex for women makes them bad unless it is in wedlock and for having children. men get raped. Gay men pay men for sex, women pay men for sex. Paid for sex is a more complex thing than it automatically equates with rape.
But none of that is specifically to do with disabled people, and in response to the link in the OP 'Dignity for the Disabled' could be better achieved by addressing the shameful process now in place to make disabled people beg for statutory support, and by stopping the ignorance and discrimination which disabled people face.
And by the way, one of my DC is disabled and I have listened a few times to people blithely saying they could never have sex with someone with that type of disability.
The prospect of your child never feeling sexually loved does make you wonder about our right to such important expression.