I thought that if an article with such title is upvoted here, it will say something interesting. Not so.

Yes, but it seems from discussion here earlier news.yc user accounts are reviewed as part of the YC application process (this has been mentioned before).

As such, even though PG would never penalize users for upvoting critical articles, I'm guessing there are some users that are paranoid anyways and playing it safe.

You're not going to be much of an entrepreneur if you're afraid of disagreeing with your investors every now and then.