> I believe that most of that clauses are there for tit for tat reasons. Someone (Oracle?) was the first to do one--and then they published comparative benchmarks showing that their product was better than the competitors.

Actually there is a good story behind it. See: "Larry Ellison allegedly tried to have a professor fired for benchmarking Oracle" [0] and the related HN discussion. [1]

[0] https://danluu.com/anon-benchmark/ [1] https://news.ycombinator.com/item?id=15886333