You have to realize that there are game mechanics that push to this.
I don't like it either, i feel a little disgusted even as a player, but thanks to the ow so loved TMP penalty, game mechanics push a realm towards just declaring war and making up reasons just to cover them selves.
And yes, this is all still perfectly realistic, most wars weren't fought with a 'valid' reason.
I still think Fronen could prevent this war if they'd use a diferent diplomatic strategy (if they had one at all).
You should know as ruler that gang bangs ocure alot in BM and to prevent them you need very stable relations.
MR Calanar(steve) knows all about that 
(hes been ruler on FEI for long time)
as mentioned before, i really do not care much for valid reasons, every ic char can have his own story and that is ok as long as there is at least tiny common sense which would allow us to feel as if we are playing against played characters, not slots that are just ganging, strategy commonly applied in many trivial online game i have seen.
i remember well, that melhed ruler was disgusted by thalmarkin's surprise change of behaviour, he reacted sharply at ruler's channel, stating his own beliefs that thalmarkin made dishonorable move, and lead to logical expectation that melhed will join fronen in war, making game at least tiny playable.
it is also not so impossible that such ruler is overvoted by his Senate, as that is republic, but what is really awkaward that he accepted to dismiss all his beliefs, acting as servant or senate.
he could, for instance, defy to senate, try to usurp power, defect to fronen, try to do
anything to show that he is character with flash, blood and beliefs, rather than acting as someone who simply wants to save his post by all means, disregarding any ic reasoning.
that is just one of many examples how people do not care for anything but buttons and cheap, too easy, non-thrilling, non-playable-by-two-sides wars.
