Normally when utility companies put installations in land they do not own, there is a wayleave agreement. That will usually include payment of a fee by the company to the landowner. Unfortunately, my personal experience is that not all companies are very good at paying the wayleave - and yet the workers still trample all over the land using it as their own. I would also be very surprised if there was not some sort of provision to allow forced access in an emergency.
It's entirely possible he IS being selfish. It is also quite possible that the communication company is not necessarily playing fair. There are generally two sides to every argument.