I do it because the tobacco will burn more evenly, I also am a believer in delayed gratification. Do your char light( preferably with a match) and then set it down for ten minutes. May not be for everyone but it always makes the bowl more appealing.
I end up doing a char light about half the time, and when I do, it is because the tobacco seems to need to settle in the bowl. It burns and expands and is no longer packed. This doesn't relate to how hard it's packed in the first place, more about how it is cut and how dry it is. I admit I'm happier when it just lights up and forms a steady ember, but you can't always choose. I take it in stride.
I do a char light with any ribbon or shag for sure, not so much out of methodology, but out of necessity. These tobacco is expand when the flame is put to them, and I find myself having to tamping them down relatively aggressively at first, which leads to the tobacco usually going out. But then, after tamping, I try to get as far as I can without touching the flame to them again, by tamping gently and often. But if you don’t have to relight, there is no reason to do so just because someone says to.
I was doing char light religiously when I started for the first couple of years. Now maybe 50% of the time. I found that if the tobacco is properly dried many times there is no need for char light as I get a nice even homogeneous light on all surface with a single match (sometime even 1/2 match). In addition to dry appropriately the tobacco another thing I am doing now is loading the pipe in advance sometime even 1 hour before actually lighting up and I suspect this help the tobacco to settle down in the bowl making easier the lighting. Now if I get a nice lighting at the first attempt I don't see any reason to let it go and doing a second start. However, if the first light is not even I let it go down and do a second light.
Addendum: Don't mean to single out a single company, and these folks might be completely innocent of nefarious promotion of match use. (thought it was old match boxes from four companies, but clearly is not)
I think a char tamping light depends on a lot of variables, just like about everything else in this crazy fun hobby. If I load up my pipe and its smoking like a champ from the get go, why stop, tamp and relight? If, on the other hand, it is packed a little loose and goes out quickly, then you bet I tamp it down to just the right density and fire it back up and puff until it needs another tamp or two.
Sounds like these two old people just started smoking pipes. It’s your duty to teach them proper form. Just because they are old and grow tobacco doesn’t mean they know everything, nor do we.
Really, I don’t always do a charring light, unless (as stated above) there is a necessity, sometimes one will do to the very end. Sometimes the tobacco expands. Sometimes it needs some fiddling. Sometimes I just feel like doing it. There are no rules to pipes. But, it sounds like these guys just felt like ribbing you a bit. You should have snarked them back. Back slapping among pipesmokers is a form of camaraderie. You gotta get you shots back in. ::