Yes a lot of postings get deleted on this site.
Even on jet blast there is a lot of heavy handed editing to say the least, not because it is senseless but because the mods don't like it or it pricks their conscience. There have been cases recently where threads have disappeared, giving me the impression that the pprune moderators on JB for instance seem to me to be pro Islamic terrorist. I know of one ppruner who got banned for speaking out against terrisom.
I guess the mods "get off" on all that power they weld by deleting threads.