I've said that to customers thousands of times over the years. Especially when the customer has an attitude and rants on about their issue. "My truck doesn't..... (whatever the issue)"..lol

Btw, you can test the accuracy of the cts, but why? It's only 10bucks for a replacement from RA.
It appears that the OP's gauge and pcm are inline with each other, however if the cts is inaccurate(for many reasons including improper coolant) a new cts will correct. However, if the temp is still reaching 213°F, after cts replacement, further inspection recommended.

More information:

Coolant Temperature Sensor
Overheating Possible Causes

 

OBII reading 213 after 1 hour and ac on, new radiator and new thermostat like I said before, don't really care much about your hummer or your attitude

 

Temp was in low 90s here with high humidity, very muggy, I have not lost any coolant from overheating, I do not smell coolant it is just the gauge reading near 3/4 but it sounds like pretty normal for the hummer which I am not use to, the OBII did read 213 at idle after 1 hour with the ac on

 

I've always taken great care of my H3, still starts,idles,drives,stops,&rides like new, therefore I don't have an attitude.

FYI, optimal operating temperature is 195°F(100+yrs of research came to that number).
As I noted above, I recently tested under extreme conditions and only deviated +6°F.
You show +18°F, and yes you can still drive it, however there is premature wear from various components occurring, while you drive!
You can accept that it's normal, or you can do more research on the effect of coolant temperature.

 

With those details, I would say with 100% confidence you are good to go as what you are seeing is normal.

Still might want to give the radiator a rinse front and back. Some people also swear by coolant additives like Red Line Water Wetter and Royal Purple Ice for some help.

One last question. When was your Trans Fluid and filter last changed?

 

Not sure about the tranny fluid and filter Doc, I just got the thing a couple weeks ago, I did replace the radiator but the ac condenser needs a good cleaning,

 

Plz make certain to block the wheels as this type of vehicle will roll when doing trans filter and fluid change. One of the very few times I've been freak'n freaked when working on vehicles.

 

Thanks I always do, got another problem now, drove yesterday and outside was 70F with low humidity, drove fine for 30 mins, temp gauge just a tick over half, stopped at grocery store and came out to leave and drove maybe a block and started missing, acting like was going to stall and had little engine power like not running on all cylinders, pulled over and popped the hood and could not "see" anything out of whack, shut it off and waited a few minutes, started and ran the same so limped it home but have not dug into it yet, I live in the hills so it was a challenge getting home, when trying to accelerate to climb the hills it would drop down into lower gear (at) and then immediately back out, like I said I have not had a chance to look at it yet

 

on these vehicles when "new to you" it is imperative to check and clean the MAF sensor and throttle body. also check and or replace the stock battery terminals. dirt or corrosion on any of those items causes all sorts of driveability issues.

 

Just went out and started, idles fine seems like to me. I took off the throttle body and cleaned with throttle body cleaner, drove it around the mountain and no issues. I will get the MAF sensor cleaned and drive it more tomorrow, what confuses me is I am not getting a check engine light or any other info