In all honesty, the ethical thing to do is to decline payout when you copy/paste these trailers. You shouldn't be paid for PSAs.
If you actually put in your own analysis, comments, etc. into those contents, then you can probably monetize it.
As of now, you are just setting yourself up for massive law suits when the authors/copyright holders find out about you. Last time I checked, Reddit doesn't pay out users for regurgitating what's already on the Internet. Karma points aren't money.
I combined my love of watching movie trailers with a nifty social network that pays you for using it. I see nothing wrong with receiving rewards for using the site as intended. People gain plenty of likes, upvotes, retweets on other social networks for sharing this type of content. I have not broken any terms of service or laws. The rights holders can revoke access to their material at any time but they won't since it's what they want. They literally pay to have these trailers shown on television.
I thought about a lengthy response, but I figure it's easier to keep it simple
tl;dr - It'll be easier if you just do a 500-word review. You'll get these guys off your back, and possibly save yourself some future headaches when the holders do notice.
Sharing with other users for free and reproducing for profit is two completely different concept. You might actually be breaking some law here I am not sure.
Regardless, if you think that reposting trailers are OK arguing that it is allowed here, then remember that flagging is also allow as an organic way for users to express displease to your content. So it is not censorship, it's just part of the game. As @enuser48 suggest, why don't you just write a small review for each trailer you post? I am sure whoever is reading it would appreciate it.
The fact that flagging is allowed doesn't support the assertion that it doesn't result in censorship. I write reviews and summary's on my main account @movietrailers has a specific theme and some people enjoy it. It serves a niche and most certainly doesn't deserve being auto spammed as a scam.
What harm do you think is being done?