I would rather the option to work from home. I just don't want a pay cut to do so.
I think the market rate is what the job was advertised for - it has no bearing on the existence of the work from home rate. If the work is exactly same it should be identical.
So the question you asked in this thread is not really a question. You have already decided and you are just looking for people who will agree with you, so you can justify your foul mood about it.
Your options are still the same. You can go to the office for one rate or stay home for a lesser rate. How much you grumble and complain about it does not affect anything.
In fact, even if you were fully justified in complaining about it, even if the company was morally wrong in this matter, it still wouldn't make any difference. You would still have exactly the same options.
You might as well choose whether you want to go to the office or stay home, and do the job and be happy. It sure beats the alternatives of doing your job and complaining or quitting your job in a huff.