I'm not offended in the least by what you have written. But what does surprise me is that you are too easily prepared to lay the blame on FT's who've been mistreated by their employers rather than on their errant employers themselves.

For many FT's it's not a matter of being able to choose their employer. If, for example, they're black males with no degrees nor formal teaching qualifications, they'll usually find it hard to get jobs as teachers in China for one reason or another. And when they have problems at the workplace and with their accommodation therafter, those problems should be mentioned in detail on the board to forewarn other newbies of what difficulties could be awaiting them. To be forewarned is to be forearmed.

The purpose of the negative posts and numerous complaints re Chinese employers who do not honor their contracts is to provide information rather than put aspiring FT's off coming to China. For example,I am aware of a Zimbabwean teaching on an F visa for a dishonest,greedy employer in the sticks here. He's got problems, sure, but they pale into insignificance when contrasted with the struggles of surviving day to day back in his homeland. So he's happy to be working in China. That said, he doesn't deserve to be badly treated because he's teaching illegally any more than he deserves to be poor and hungry in Zimbabwe.

But back to the issue of probationary periods for FT's in China . Good reasons have been given against it, which those on the opposite side have chosen to ignore. Now I've no problem with that. I believe my view on it is right. So I'll not work for an employer who insists on a probationary period if I have other offers on the table -not because I'm afraid of being assessed, but because I think probation is unnecessary here. And other posts in this thread have already gone into why in depth.
As for ropey Chinese employers, they exist across the board in the EFL industry here - I've had bad ones in both the public and the private sectors, both in secondary and in further education. But, unlike you, I've never taught at any top universities here, of which there are precious few, by the way. As for working for average or even excellent Chinese employers, fine, no problem. But let's highlight the other side of the coin and not give the bad employers more powers such as probationary periods just because we want to weed out some bad teachers working for good employers. The procedure is already in place to do so in the standard contract.