They used to be treated very poorly, sometimes exceedingly poorly. In the modern era they are generally treated with more respect than they were historically, despite almost everybody having lower expectations of them.
As cruel as it seems to us now, if you're struggling to survive and there's no social safety net, infanticide or child abandonment start to become much more attractive options in comparison with being burdened by taking care of a dysfunctional human for the rest of your life.
(around 70 IQ I think, but sources are very much in disagreement on this, claiming it's more around 25-50 [1]. Taking tests on animals is hard)
Last I checked they were all in the "critically endangered" category [2].
[1] https://www.quora.com/Using-human-standards-what-would-be-th...