Inter-branch slagging is older than the RAF and there is no reason to believe the FC branch is viewed any more dimly than any other branch by the wider RAF.
I recall that WCs and IDOs fall into the Wpns vs Systems banter mode during training and for a short while after but that this is largely forgotten about after some ops room experience and some time in the branch, when banter at the personal level becomes far more fun, on those occasions when banter is called for (it was normally Friday nights).
The training regime included some crossover of knowledge between the WC and IDO specialisations when I was going through the CRC, and during the later periodic standard evaluations. I've known IDOs to give out a broadcast picture on radio during exercise, which requires some knowledge of what aircrew want for situational awareness and an understanding of the WC task. Working in silos in ignorance of the wider team is no way to get on, whether in the military or in civilian life, and learning about the other roles (whether in the ops room or in the more boring office) helps the overall team effort.