This is legal communication written by a lawyer and intended to be read by lawyers.

Consistently, the first thing every lawyer has said to me when preparing for any interaction with third parties that had a legal aspect was "never volunteer information you were not explicitly asked for". Of course lawyers would practice this among themselves. The law requires him to suspect something wrong to investigate, so he states "I hereby formally suspect something wrong". If the investigation leads to a court filing, the law would then require him to submit evidence, so he will strategically decide which evidence to submit and submit it. Why would he commit in advance to what evidence he believes relevant if not required by law?

But also, if reading the letter as if written in good faith - which I find hard to do - those are all true reasons to suspect something wrong (it is common knowledge and well established that Wikipedia is a very influential source of knowledge, and that there are attempts at foreign influence), and great questions to ask to investigate whether the Foundation is making a reasonable effort to fight it if you were a regulator or auditor or other investigator, all of which have great answers already written up that prove the foundation is doing a very good job at establishing and maintaining processes to ensure the neutrality of its articles. In my headcanon, Wikipedia's lawyer responds simply with a list of URLs.