Another possible (unspoken) reason why Gariépy is resigning is presumably that he's been a postdoc[0] for the last 3-4 years[1]. Unfortunately, the nature of modern biomedical research is such that you need an army of researchers to do the mechanical grunt work at the lab bench that leads to papers. This has led to a glut of postdocs, who are underpaid, overworked, and have little hope of ever obtaining a permanent academic position[2]. And even at top universities, industry positions are quite difficult to get without putting time and effort that you don't have to spare into extensive networking[3].
During his postdoc, Gariépy's had one second-author publication in Nature Neuroscience[4], which probably wasn't enough to get a tenure-track professorship. If, like the first author on that paper, he had gotten an assistant professorship at a prestigious university[5], he probably wouldn't be airing his dirty laundry. Also note that he is a YouTuber[6] and has a book coming out according to his Twitter profile[7], so he's probably trying to leverage any notoriety he gets from ragequitting his postdoc to jumpstart his career in science journalism.
0: http://today.duke.edu/node/132805
1: https://www.linkedin.com/in/jeanfrancoisgariepy
2: https://www.bostonglobe.com/metro/2014/10/04/glut-postdoc-re...
3: https://www.bostonglobe.com/business/2015/09/02/cambridge-pl...
4: http://www.nature.com/neuro/journal/v16/n2/abs/nn.3287.html
5: https://medicine.yale.edu/neuroscience/people/steve_chang.pr...
6: http://neuro.tv/
7: https://twitter.com/JFGariepy