This is true and I agree, however the issue is that it's currently starting to be really difficult to rely on allies, given what's happening with US and some other NATO countries. Honestly, and of course this is just a personal preference, I'd rather we currently spend more on defense because of that. Of course, if the situation was different (i.e like two years ago), I'd probably not be that much OK with it.
I'm also not saying that we shouldn't spend money on anything else, but budget creation is extremely difficult topic, and my main point is that I really don't like how "spending on weapons" is used as a scrapegoat from lack of proper social budget, because it is clickbaity. There's a lot of other, more serious, budget issues that could be focused on. This kind of "anti-war" rethoric plays right into the hands of Russian hybrid war, which is (unfortunately pretty succesfully, which is why I'm speaking against it so vehemently) framing any kind of increased budged spending as warmongering, and that is something that is more likely to get people like me into trenches.