Let's take your argument at its face value. There has been some disappointment with joining the EU and the economies have not performed, but that doesn't mean there's a huge rush to embrace Russia in any way, shape, or form.
In fact, if I were a leader in any one of those countries, I would be a little bit nervous about Russian military exercises up and down my border. That would get me concerned. I realize that standing up battle groups in Latvia, Lithuania, and Estonia is a glorified speed bump to any incursion. The Russians could take them in half an hour, but they couldn't hold them. They can't hold them.
The history of those countries is simply a pathway to exploitation and oppression. So their history, their economic circumstances, and their realistic assessment have led them to what I'm hearing you say is an irrational fear. I'm not sure that it is actually irrational.