> Yes, we pay to defend Europe from Russia, and we do it for free.
If 'we' is the USA, then I'd suggest the USA pays to maintain a very lucrative industry, and as far as anyone can tell, they pay way over the going rate, and have very poor book-keeping.
The idea that some older equipment, rather than being retired or disposed of, is being sent to Ukraine, as somehow being exclusively a defence of a distant place, and 'for free' feels asymmetrical to reality.
The USA has some serious risk / concerns coming out of this conflict - not so much petroleum products, but certainly iron ore, argon, neon, cobalt, etc. That's the practical resource based risks, and then there's the whole regional stability, opportunity to assist in the downfall of an enemy empire, etc etc.
> We should stop doing that, and invest more in domestic needs.
If 'we' is the USA, then I suggest you won't stop doing the former, and you won't start doing the latter.
In the past twelve months the USA's sent US$30B (list price) of equipment to Ukraine.
That's out of an annual budget of around 1,900B (or 845B) depending if you're looking at resources or obligations, but either way, 30 is a small component of that.
For context, the most recent US DoD audit identified at least 220B worth of equipment that they simply can't determine the whereabouts of.
So, yeah, I reckon the USA could look after its own interests by sending some equipment to Ukraine and address homelessness within its own borders, if it really wanted to.