It's not irrational when your companies lawyers say that you many not use React due to the licensing, and there is a very real chance you will be terminated if you do. Unless you mean that lawyers are irrational, in which case I would agree (throwing in judges and politicians and anyone else in the legal profession while we are at it).
With the old patents license, you had to be the one to initiate patent litigation with Facebook. The odds of needing to and wanting to get into patent litigation with Facebook are way less than 1%. That's an irrational fear. If something has a 1:100,000 chance of impacting you...I dunno man, when it comes to startups I can think of 1000 other things more likely to affect you. Companies that didn't even have patents were getting up in arms about this. It was quite a bit of irrational FUD. Even Wordpress's lawyer didn't have a problem with the license. They were just tired of fending off the FUD from their user base.
