I few people mentioned that it was hard following what I was saying. Let me put it another (albeit extreme) way:
Hypothetical: If one was NEVER able to burn off soot by getting the exhaust hot enough, and ALL soot burn-off was ALWAYS a result of regeneration, other than using more fuel, is the DPF (or anything else) being harmed?
Now back to my situation: I picked up the Jeep with 21 miles on it and I drove it home at sustained high speeds (up to 80mph) for 40 miles. When I got home, a Scangauge showed 63% level of soot. And...this is the soot level after just 61 miles, with 2/3 of the miles being high-speed highway miles. 80mph + 104 degrees ambient seems like the DPF should be loving life - not building up soot.
The soot is always going to burn off as a result of regeneration, either passive or active. Passive regeneration, which you have experienced, is ideal because the engine is not injecting any additional fuel to assist with regeneration. It is accomplishing it based upon the high heat already present in the exhaust system.
Active regeneration is accomplished by injecting raw fuel into the exhaust during the exhaust stroke of the engine where it will ignite and raise the temperatures downstream to allow the soot to burn off in the DPF. The negative effect of this type of regen has been known to be worse fuel mileage but also fuel dilution in the crankcase, which can wash down bearings and lead to premature engine wear and failure. Therefore, passive regen would be the ideal way to handle the soot.