At the end of the day, these are companies dealing on mistrust. When you use a proctoring service like this, you're assuming that people will cheat. And when you make that sort of assumption about someone, chances are that they will.
I personally can't respect or trust anyone who isn't willing to trust me, before even knowing anything about me. I can't trust someone paying, directly or indirectly, so that someone/something can spy on me to confirm their unfounded mistrust.
If I told you, with no alibi, that I don't believe you'll grade my work fairly, and mandated that you give me access to your webcam, microphone, screen, keystrokes, driver's license, etc. whether directly or through a third party, you'd understandably be pretty fucking pissed off at me. Why is it fine when you do it? What right do you have to barge into my home, holding my grades at gunpoint?
Not to mention that if your test/exam/assignment is worth cheating on, then that means it probably isn't very good to begin with. If students aren't deriving value from your course material, if you fail to engage them, whose fault could that possibly be but yours?
Why am I being held responsible for YOUR failure to engage your students? I just don't understand.
If you teach English 101 or Algebra 1 or some other required class, there are going to be cheaters, and there's not much you can do about that. All you can do is improve the quality of your material in the hopes of making it more engaging. Show them why you care about your field, make them do actual, meaningful, relevant work.
No amount of proctoring will stop someone who is determined to cheat. Any amount of proctoring will hurt good students.