Not the case here.

My email message to MC stated only that the rate on Hotels.com was lower.
I said nothing about the side issues (internet, breakfast, etc.).
MC responded to me that hotels.com does not qualify for the rate match.
I am happy to send copies of the correspondence to anyone who wants --
including the MC folks.

It is clear from all the posts that the rate guarantee is not consistently applied.
My guess is that the higher up you are in the MC loyalty programs, the more likely you
are to have your rate matched. I see no other explination.