Agreed... and disagreed. Yes, if a nation is at war, it should be able to ask for help once or twice at least, and yes, refusing definitely shouldn't make them happy. After all, they're depending on you.
...However.
Many nations do spam such requests excessively - if I'm, say, Sardinia-Piedmont, France really does not need my help with Mexico. But they keep asking for it. Now, it would of course be easy just to accept and not send any forces... but, you know, war exhaustion - depending on the situation in the country, by the time Mexico is about ready to accept my 'status quo' peace offer, I may already be fighting a dozen rebellions. In this context, the help-request-spamming is really, really irritating - you either lose stability or years of diplomatic efforts, just because the AI could not correctly assess its situation (and because the population of your country cannot correctly assess theirs - why do they get war exhaustion from a war with Mexico, when this war involves no fighting at all?).
A part of the problem is not so much the annoyance of such spamming, but simply the player's inability to fix the damage, because of the limited availability of diplomats and their high costs - in terms of diplomacy, Victoria is simply nuts! This is the 19th century, many nations have permanent diplomatic missions in other states (at least the major ones), and I'm limited to one or two (hyper-expensive) diplomatic actions per year? What's more, the chances of improving relations more than 10 points are insanely low - there's really nothing comparable to the dilemma of someone playing a small European state like Greece and wondering whether the $500-1000 they're throwing to Austria would have been better spent elsewhere. In EU, a common tactic was to save a game before offering to diplo-annex a state, and just keep loading until they accept it. In Vic, I have found myself on more than a few occasions saving a game before something as simple as improving relations, because Vic's diplomatic system makes these things so difficult. It certainly doesn't help, either, that diplomatic relations, if left unattended, always get worse with time. The fact that, as Greece, I have never had a reason to spend hundreds of pounds on relations with the US does not mean that they should hate me. Certainly, they would have no reason to have great relations with me, but a level of friendly neutrality would not be too much to ask for (at least if my government's constitutional). This doesn't really affect the game that much (since the US will never attack me anyway), but it still looks very strange when you notice that most of the world dislikes you even though you've never annexed anyone or taken any province you didn't have claims for.
