The refutation is that the principle of verification upon which positivism rests is not empirical or tautological, which are requirements for meaningful statements. As such, the principle is neither verifiable nor meaningful.

My understanding is that the logical positivists were unable to satisfactorily answer this critique, and so it failed as a movement in philosophy.

Scientists aren't expected to be well versed in philosophy, so it's not a surprise if some or a lot of them naively hold on to philosophical views that have been heavily critiqued. Most of us probably hold such views, just like a lot of us have scientifically naive or invalid views.