One of the best things about riding with folk is the piss ripping that occurs. Pretty much everyone I know reckons that the banter is the highlight of any ride, and likewise most forums.
Fact is it is a big belly, and it is a nasty injury. No one was actually intending any offence, as is reflected by the apologies, and to be honest the reaction says more about you, Derek than it does about the p-rippers. I very much doubt that anyone on here is anything other than supportive of your efforts to get fit, sympathetic regarding your injury, and grateful for the warning.
You can choose to be offended, or choose to believe that having the micky taken is the equivalent of an arm round the shoulder and a bit of support from people who don't do huggy kissy.
You'll find your life is much more pleasant if you choose the latter.
You are welcome any time on a ride with me, but lighten up fella. (You can choose how to interprete that too!).