Generally because routes are setup a certain way and the more 'one off' fixes put in place the more the scope for problems further down the line.

We also do not know what all the other traffic is on this route that would be affected.

In the OP it says

a re-route of the traffic would affect more than just the gamers on this thread, the traffic to these servers also include all BT Vision and BT Sport traffic as well as various other businesses and Broadband users, so for this particular instance a re-route is not an option.

In reply to a post by Chrysalis:

haha, will they just keep locking new threads?

Yes, that's what they keep doing. The only testing they carried out was to play a game of FIFA between themselves and it worked. They looked at some traceroutes but these didn't tell them anything, even if they knew what they were looking for.

From these tests, they decided there was no fault even though people have been reporting problems for years.

What they didn't do was monitor anyone's connection who reported a problem.

sometimes it pays to just look for the noc contact and email them direct.

More than once I have got routes changed this way, it bypasses the entire tech support heirachy.