They are probably correct.

This depends upon A LOT of factors. My 243 and 58 gr bullets shooting CFE uses 43.8gr. The 22-250 with the same powder and 40gr bullets uses something like 2gr less. So essentially the same amount O powder, in a smaller surface area. This means much higher heat/ flame erosion. Now what does that translate to in the real world? Who knows.
Will the barrel withstand the match? Should. Will it be a 5,000 round barrel? maybe, but probably not.

In my weather right now, 1 shot per minute with my 308 wouldn't get the barrel warm enough to cuddle next to. It is in the 70-80's midday, with a 10-15 mph wind. Heating is not an issue. If you are 100+ and no wind, good luck...