Can we Re-upload the rejected videos.

Yes. I would if I thought a video had merit. Usually, a video can be improved by doing some or all of the following depending on the video tone.

1. Make it shorter. A shorter video is better, usually.
2. Get to the point. Start with the best part of your video don't let the video drag. People decide to watch or not watch a video in as little as 3 seconds, make each one count and have it be a hook for the viewer to watch more.
3. Have a descriptive and short title with a great, catchy, description.
4. Production value. Add music, tweak the sound so everything is audible, tweak the color/contrast/brightness so it looks as good as it can, reduce shaky cam if needed.
@ThrowbackHomeVideos, you said to add music, but so far all of my videos that had music were rejected, even "one of a kind" ones, so it made me wonder if they're rejecting them because I don't own the music...
Rumble definitely should tell us why a video got rejected, so that we won't make the same mistakes over and over again!
Thanks, @cseh_17! I had used those songs you can add on youtube... but then you can only add music to your videos if your the composer?! I'm pretty sure I've seen videos here with random music... not to mention all the cover versions, they don't own the music...
The first time I added a video with music, I asked Rumble first, and they told me to upload it and if there was a problem, they would let me know... the video got rejected, but I never heard back from them.
It's tough to say without seeing and the videos. Link a couple and I'll let you know my thoughts. As for music copyright. If you cover a song and want to make money off of it you need to purchase the rights to do so. Many song publishers allow covers as long as they are not monitized. Make sense?

One loophole around this is a parody song that changes the tone (usually in a funny way) and the lyrics. The instrumentals have to be original too but they can match the original without issue.

YouTube offers 2 types of music for use. One is royalty free and able to be monitized. It is usually instrumental. Then there are songs that can be used but not monitized. These are usually from larger artists like Taylor Swift.

Does that help?
I got a copyright issue on one my YouTube video yesterday for a Bollywood song. YouTube said that video won't be monetized.So I think videos will get rejected if they have music which you don't have license to use them.
It also is a copyright infringement. It also is in case of concerts, and events.
Now if the clip is really short, or in the background, you may get clear with it. I don't know, give it a shot!
@trarau, I had a video once that had a couple of songs playing in the background, and it was accepted for limited distribution, so I guess it's ok, as long as it's not "too obvious", if you know what I mean.