Voyager used the Bussard collectors ramscoops to collect radiogenic isotopes from Vaadwaur planetary atmosphere and use them as a power source. They were also used to gather Sirilium from a class 17 nebula, and plasma particles from astral eddies. On all 3 occasions Voyager used them as a way to supplement the ships power. Enterprise-D used them on 2 occasions to release specific elements. Enterprise-E used them to collect the metreon gas from the Briar patch to help them in subduing So'Na ships (well, the So'Na pretty much did it to themselves when they fired on the gas the Enterprise released). So, yes, the Bussard collectors can pick up and blow out matter (or filter specific elements from collected matter), however that doesn't appear to be their sole function... seeing that we DO have some observational data which can support the premise they aid in creating extra energy for the ship - so the statement wouldn't be incorrect (technically speaking). We have no direct observational data (at least nothing from on-screen evidence) which suggests the collectors clear path through interstellar space (the main deflector dish is what moves interstellar dust etc. away from the ship).