It’s not about a sudden sensitivity to Russian feelings: NATO is not providing up-to-date weapons and ammunition for excellent practical reasons:
The Ukrainian armed forces use Soviet weapons systems. These are well-designed, solid, easy to use for a conscript army, and although the Ukrainian inventory may be aging, Soviet arms production was never geared to high-tech generational obsolescence. They build simple, solid and cheap because they have to. NATO countries are casualty-averse and never commit a platoon where a Hellfire missile is available. On the other hand, Soviet doctrine never varied much from the World War II stories of tank attacks shoving the flaming hulks of the first wave out of the way, for the second wave to be destroyed in turn, until the Germans ran out of ammunition. Almost anything NATO could supply would be very hard to employ on the battlefield without training, and time for training is what the Ukrainians do not have.
In this sense, “training” doesn’t just mean “here’s the operator’s manual.” It means that the whole operational and tactical doctrine of the army has to be redesigned around the new weapons systems.
It’s not just the actual weapons, training and doctrine, either. Not to be unkind about it but Ukraine’s armed forces are almost completely hollowed out by official neglect, underfunding, and corruption. Back in May, Sarah Chayes reported on the pitiful state of Ukrainian military preparedness:
In a 2012 analysis Leonid Polyakov, another senior defense official, detailed the corrupt workings with remarkable candor. Chronic underfunding “enhanced the role of the human factor” in choosing among operational priorities. Ostensibly outdated equipment was sold “at unreasonably understated prices” in return for kickbacks. Officers even auctioned off defense ministry land. Gradually, Kyiv began requiring the military to cover more of its own costs, forcing senior officers into business, “which is…inconsistent with the armed forces’ mission,” and opened multiple avenues for corruption. Commanders took to “using military equipment, infrastructure, and…personnel [to] build private houses, [or] make repairs in their apartments.” Procurement fraud was rife, as were bribes to get into and through military academies, and for desirable assignments.
So even if Ukraine had taken advantage of NATO equipment, training, and support, much of the new kit would have disappeared into the same criminal enterprises which sold off so much of the old kit.