The bottom line from the article is that, more likely than not, that Russia's objection to Ukraine joining NATO underpinned Russia's behaviour towards the Ukraine since 2008.
The article's peamble accounts for your type of rejection of such claims is self explanatory.
IMO the sure way to testing this is for both the Ukraine and Russia to enter peace negotions uninhibited by external powers by laying all their respective National Security issues on the table with the intention of reaching a mutually acceptable/enduring/enforceable compromise.
In the meantime the "more probable than not" judgement is OK by me.
