i do not seem to be able to do that. even if i set the app to display a specific feed (vegans, or friends, etc) when i back out and launch it again, it defaults to 'what's hot' or what is known now as of the latest update as 'all circles'
the post in question is but one of many, and most of them are from friends. as i can tell, it's just some odd theme that happens on Sundays. not sure what started it or why it just happens. Almost like an unofficial G+ holiday. everyone just posts that crap as if they're supposed to. all with that hashtag. worse yet, Google appears to have removed 'block offensive content' in settings, basically reducing Google+ to be a 6 day endeavor and avoiding it on Sundays. never did like porn.