I don't misunderstand that at all.

But I'm curious where the line between acceptable and unacceptable "profit" is.

In your reply, you seem to indicate it is to be found around here:

"but a corporation doesn't own the police force with the expectation of making a profit."
"But the hospital isn't owned by a big corporation who expects a huge return on investment "

"the 'investment' element is removed".

That is, the ownership of the capital required for the enterprise is the issue. You seem OK with profit for labor.