Their statements were worded to state they were probably ineffective for healthy people to wear for their own protection in the general environment. That is probably true in that the point of masks is mostly to protect others. So if you don't have enough masks (for total coverage,) a higher risk group using them all was not going to be effective in protecting the high risk individuals unless they tend to cluster.

Correct. It was always said if someone was sick they should wear a mask (more studies have come out confirming this). Once asymptomatic became such a big transmission vector it made sense for everyone to wear a mask. PPE was/is still an issue, so cloth masks were also questionable early on, but have since shown effectiveness.

https://jamanetwork.com/journals/jama/fullarticle/2768532

More precisely they stated that there were no studies proving effectiveness. They were hiding behind the scientific method to serve some other purpose.

I think the problem is rather that the public was looking for ideally easy and hopefully definitive answers and were confused when they saw scientific progress unfold in real time instead, with all uncertainties, theories and what it entails.

I definitely had a good share of discussions revolving around "scientists are saying different things every week" in the last few months. My closer connections seem to understand now.