They agreed that war was a thing of the past, but still continued to push for NATO to allow new members anyway, ironically causing Russia (and China and everyone who is NOT in NATO) to suspect that war was NOT a thing of the past and therefore never quite abandoning their military completely. Unpopular opinion: the West should either NEVER have abandoned its military production (so as to maintain NATO actual preparedness for war, given that's the only reason for its existence) OR it should just have dismantled NATO and announced to the world that it strongly believes war is a thing of the past, and that other countries are advised to follow suit. But we actually chose the easy, halfway path: keep NATO, keep our militaries "looking strong" (which gives the signal our rivals should also do the same, obviously), but not actually be ready for any sort of major war and as the article points out, even lose actual capacity to become ready for war within any realistic timeframe. The worst possible outcome :(.
It could be matching theory for outcome though. The unpopular opinion may still be wrong too. Russia was quite different in 1999, or better in 1992, to the point of joining NATO, and China was nowhere the threat of today, and it could be different reasons- not keeping NATO - which caused today's standup. So, basically, the situation seem to be more complex.