There seems to be a lot of black and white opinions on this rather grey matter.
I still maintain that on the facts presented, it is a go rather thin excuse not to fly.
There are plenty of factors which are not presented which may alter my take on this. If the worn seal is a howler then the company should be replacing it for the passengers' sake. There is no mention of time of day, schedule, congestion, weather or maintenance bases. These would all be taken into account in the decision making process.
Very often people who fly for the kind of outfit which Gulfstream appear to be have a bit of an axe to grind with them. I wouldn't be surprised if this also plays a part in the process.
I have known of people who try to find reasons NOT to fly rather than to carry out the job for which they are paid.