author here. yes, i have been working on adding subtitle support to this web app as well (you paste two urls, one for the video and one for the srt file). chromecast supports WebVTT [1] and it's pretty straightforward to convert srt to WebVTT. Although, it requires using a custom receiver app. stay tuned.
It's not that different than speaking in person actually, except you don't have to pay attention to the reactions of others to see how your statements went over (in aggregate).
Although posting a comment saying that you decided not to comment because everyone would downvote you is likely a very good way of... getting downvotes.
Say what you want and how you think, but be prepared to support your position with something more then conjecture and posturing. If in spite of providing support for your well articulated and argued position, you receive down votes, hopefully someone has left a reply that will help you to understand why others disagree with you. Take it as a learning opportunity. You don't have to change your opinion, but use what you learn to help you write your next comment.
Dissenting opinions on their own won't usually give you down votes, but unsupported inflammatory remarks will.