if you read the post, you'll notice it is in the manifest and priority is set.
When you do exactly as your guide says to do, in Diploacy 1.32, it provides all the races you want, but do not allow you to scroll foward past the first custom race. Instead, it only allows you to scroll in reverse. To someone who doesn't know how to reverse scroll, having the custom race as the highest entity appears as though you've only access to the first custom race. Resetting the priorities for them all and putting the custom races as lower priorities makes it appear to the player that only knows how to foward scroll that all the original + one custom race is present, but how can player get back to other races? Well I click back, and can endlessly do so, but I am unable to do so in the foward direction.
If you still have no clue, then I might suggest you make a guide for 1.32, as I noticed the guide is out of date for diplomacy and that the files are as well.
Try these simple steps from scratch, a new mod.
New player entity, placing the priority as 0, and giving phase 1, advent 2, Tec 3. Then put the new race into galaxyscenariodef. Then put the new race into entity manifest aswell. Make sure everything else is unaltered and provided with replicated references to the original race it was copied from. It should provide glitchless scrolling both foward and back.
One thing I also noticed in 1.32 is that many files have improper number for brushes and even in the entity listing. I had to up the number more than 1 on my first entity listing to get the entity to work. I did a line count of entity manifest, the original, and it was more than 5 below the actual amount. Of course, I subtracted 2 for the first 2 lines which are not entity.
There seems to be a like of screwy things in 1.32 diplomacy.