The op specifically compared Serra and McGregor, so why are you stating that it would be an interesting argument to hear?
The loss to Serra is what hurt StPierre’s brand in many eyes and it also happened at his peak. The op went out of his way to address McGregor’s tap as “cowardly”, while tapping to strikes as basically a “TKO”, which it’s not. Whether you believe StPierre quit or not is another argument, but don’t tell me this wasn’t some lame attempt to save Georges credibility by taking a dump on McGregor.
I've no idea what the OP meant, I don't know what he usually posts. The question of tapping to strikes has been around a lot longer than GSP. It started in judo a century ago, when it was considered cowardly to tap to chokes or locks (and in fact one reason judo banned leg locks in 1925 was because judoka weren't tapping to them in competition (in practice it was always okay), and there were too many knee injuries, which had far worse consequences than broken arms). Boxing had the same attitude to giving up, it was how people thought back then -- people were still dueling to the death for insults at the time, so what was a torn knee or broken arm to people ready to die over a few words?
Other sports had the same attitude. Old time hockey players played in the NHL with broken ankles and hands, were knocked out on back on the ice the next shift. Goalies played without masks, skaters without helmets. Because getting severely injured or even killed was part of sport, and not a big deal.
Tapping in competition slowly became acceptable in judo after WW2, mainly because people against it slowly got old and died. There are still judoka who refuse to tap to chokes and even armbars in things like the Olympics, but they're pretty rare. Its just a sport, not a test of courage is the common viewpoint.
I don't know BJJ's history very well, but judging by Helio's refusal to tap to Kimura's kimura, it had the same attitude to tapping to chokes and locks as judo did back then. And that attitude changed in BJJ as well, so now they tap. MMA inherited BJJ's attitude to tapping to chokes and locks, and boxing's attitude to strikes.
That was fine, except about ten years ago medical science figured out that being hit on the head when you're already concussed has severe short term and long term affects (much worse than being hit when not concussed, though they're not exactly sure why, probably because of inflammation and swelling) -- affects nothing medical science can do anything to fix. Once the neurological damage is there its yours for life. That's why the NFL and NHL now take concussions very seriously, and rules say you have to be taken out of the game if you're hit hard enough to get a concussion (ie hit hard enough to be staggered).
That new medical knowledge is working its way into MMA, and fighters who know a bit about medical knowledge are taking it into account. Sparring in MMA used to go for knock outs, now many clubs don't allow full head contact in sparring. And many fighters are treating knowing they can't escape in striking just like they do in chokes or locks -- which only makes sense. A head blow on a concussed skull is far more dangerous than an arm lock, which is why medical associations want to ban boxing and MMA, but none want to ban judo or BJJ.
There's always a chance to escape. This is true for locks, chokes, and strikes. Its why Helio didn't tap, why judoka looked down on people who tapped to locks and chokes, why boxers weren't supposed to give up until they were out cold (though some would take a dive at that point). But the risk to reward comes into play. Why risk permanent brain damage or a broken arm when your chance of escape is almost zero for a sporting event?
GSP is irrelevant in this, he's basically retired and probably will never fight again, so he's not ever going to be in a position where he has to decide whether to tap or not. His tapping is ancient history. The question is about guys still fighting, and how they should react, not about what happened in the past.