Keyboard scientist

A keyboard scientist is someone who comments or remarks (usually on a YouTube video or Reddit thread) about a scientific matter as well as sharing their 'scientific' opinion trying to look knowledgable while knowing very little about the matter in hand (usually for attention).

<replying to a video about vegans>
OMG, being vegan Is totally healthy for you. I'm a vegan expert and I KNOW that eating meat is bad for your body construct.

BTW I'm not a keyboard scientist Im actually a vegan expert.