Hanzou,
No one is saying that biting negates skilled grappling but it can make the situation tenuous and potentially dangerous for a skilled grappler or even perilous if he looks at it as
a freebie.
Instead, what I am saying is that you better take it into consideration and have a game plan if it happens or how to prevent it in the first place.
It can be very dangerous to you if you do not.
Also, the guard is a neutral position. It can be an advantageous position against the right person but it could also be an incredibly poor choice to choose in a moment of violence against the wrong person or in the wrong setting. Anytime you are on your back/side in guard you are working to improve your position. Sure there are solid submissions those submissions skill sets do not make it a dominant position like the mount, back, crossbody, etc. I have a strong guard and open guard game and can play the rubber guard, mission control, etc. but I sure as heck do not want to be in it on the street. I would much rather be in the mount, back, crossbody, etc. Or even better standing up with a weapon in my hand if warranted. The guard is a neutral position in the BJJ hierarchy of positions.
Sure it can be dangerous but.... it can be dangerous to be in it as well.
Funny thing is I know people (ie. Collegiate athletes from a major university) with no training that would dominate most average BJJ guys in their guard based on their attributes alone. (purple belts and lower) I know a powerful man that your guard, my guard and probably even Tony's guard would be of little help. (Tony would probably fair better just because of his size) Yet, when you are dealing with a 7 foot 300lb man being on your back is just plain going to suck. He is not even the scariest person attribute wise that I know. That guy is just 6 foot 2 but probably about 4 feet across and has all functional strength from his job. Crazy strength.
There is always a counter, always an opening, always someone whose attributes outmatch yours and may beat your training, etc. Take into consideration these things and do not be so dismissive.
It is like you read the BJJ bible and everything else is wrong. You may find that the bible you are currently reading may not be all you believed it was down the road. Understand that BJJ has a very small market on violence.
It is exceptionally good at what it does but.... it isn't the end all be all. If it was, a pure BJJ stylist could still dominate in MMA. Those day's are long gone. BJJ stylists need BJJ, some wrestling training, Striking, etc. just to be competitive. There is a whole big world of martial training out there beyond BJJ.
Take a look and you may find that there is a lot more you could add to your skill sets! Since you love competitive martial systems why not add some Muay Thai for striking. Plus explore some non-competitive skills like firearms and blade training to round out your skill sets. That may open a whole new world for you!