all gps tracks in Josm?

If I download ‘OpenStreetMap data’ and ‘Raw GPS data’ in Josm am I getting all the gps traces that mappers have uploaded to the ‘openstreetmap.org GPS Traces page’ or just those within a particular time frame.
It sometimes surprises me that some tracks are amply covered by gps traces but others that would seem to be almost as popular have no gps trace.
Can gps traces be deleted by mappers?

Looking at my own profile on osm.org I can see my tracks that I have uploaded, and by clicking on each I get an option to delete them. So the anser is: yes.

Furthermore you can label each of your tracks to be visible only private or public.

After downloading the gps data for a small section of Dusseldorf, I am convinced that all are included in a Josm download and I’m envious of the quantity and coverage of data you have in parts of Europe.