Paul, This is a topic, I've seen mentioned before but never occurred to me.
Pulling punches to garner favor for a chance to get a repeat invitation seems like small reward for basically lying and losing one's own credibility. However, being sensitive to someone else's position, is clearly part of being aware enough not to be overly critical. Granted, the greatest courses in the world should have little to be critical of.
So, it boils down to why someone bullshits. For me, Life is too short to sell ones soul for another chance to tee it up at a course you've already payed and see problems with.
Ran and Ben really do the best reviews and when they don't like something, they will likely just not mention it. Choosing rather, to accentuate the positive. Which is really cool because then one needs to sleuth out what isn't said, to understand the review on a different level.
Fine lines indeed.