Pretty common amongst the passionate vegan population in my experience- have quite a lot of veggie/vegan friends......had one particular pal who went full-on vegan evangelist though. Had to turn him off on FB because literally every single post (often multiple times daily) was vegan propaganda - slaughterhouse ‘hidden cams’, clips of dogs being skinned in the Far East etc etc etc plus very regular reminders of how stupid we were to drink cows milk and suchlike. He changed his profile name to John Vegan Smith, got a massive vegan tattoo, the lot.
Each to their own.......but there are plenty that are preachy and beyond.
Plenty that are non-preachy too. As with everything, the shouty few tend to skew the debate.