I've noticed that since the "redesign" a couple months ago. Someone wanders onto a thread that is actually fairly tame and seems shocked at the tone of the debate.
If you do not wish to see RF posts, do NOT use the "everything" option on the browse. Instead, browse by "News/Activism." When you log back in, the browse will reset to "everything" - so be sure to set it back to "News/Activism."