Not entirely true. I am vaccinated and know that I can still get the virus. I am 99.9% confident that if that happens I will be just fine. But what if I were to have the virus and not realize it? I could give it to someone who is either vulnerable, not vaccinated or both. I don't want to see anyone suffer or die needlessly. Me personally, I still wear mine at times to make others feel at ease or as a sign of respect. I don't wear it when at the gym but I also train at a time of day when the crowd size is very small. I see your point though and by and large, I agree. But, there is some value if not scenarios where vaccinated people wearing masks can still be of benefit to others. It's the whole brothers keeper thing. I have a good amount of dickheads at work who are neither vaccinated nor wearing masks even though my place requires it. So when I go to the bathroom and there are people in there not wearing masks that I don't trust, I'll slide mine on. Scenario's like that. I'm not forcing it on anyone and nobody should be triggered by what I do.
If you and Grape Ape take me to Yankee stadium someday and show me around the big apple, I'll open your water and beer bottles for the night. Promise. 
Would gladly take you to YS and buy you the Lobel's steak sandwich, and discuss trading Spencer Torkelson to the Yankees.
I look at it this way from a math standpoint:
If you are vaxed, you have a low probability of contacting the virus.
Even if that happens, the probability that you're an asymptomatic carrier is even lower.
If you are these, then you encounter and unvaxed person during this incredibly short window of carrying, transmission is extremely low inside unless close proximity, and nearly impossible outside.
So, compounding all this, the probability that you are vaxed, an asymptomatic carrier, and are in a situation where you could transmit to an unvaxed or compromised individual is almost statistically zero.
So, wearing a mask in this situation perpetuates an irrational fear that we need to get away from.
