Funny, I had the exact same thought when we were discussing this at work today. I can't remember who's it was, but I remember fairly recently there was a bit of fuss over a group of referees going on a stag do during the week and then turning up to officiate at the weekend.
So there obviously are top-flight referees who count other top-flight referees among their close friends. And it's probably fair to say that other SG1/SG2 referees are the people who stand to benefit most from Madley being sacked: the former would suddenly find themselves one step closer to an FA cup final and/or a FIFA badge, and the latter group would know that an SG1 referee being fired or demoted would open up a space that they might be chosen to fill.
And as @RobOda suggests, there are certainly some opportunists out there. It wouldn't surprise me at all if this had something to do with it.
So there obviously are top-flight referees who count other top-flight referees among their close friends. And it's probably fair to say that other SG1/SG2 referees are the people who stand to benefit most from Madley being sacked: the former would suddenly find themselves one step closer to an FA cup final and/or a FIFA badge, and the latter group would know that an SG1 referee being fired or demoted would open up a space that they might be chosen to fill.
And as @RobOda suggests, there are certainly some opportunists out there. It wouldn't surprise me at all if this had something to do with it.