Newgrounds is not YouTube.
Uploading stuff you did not create or which contains copyrighted samples is a *massive* no-no. Violating copyright rules is a big headache for a relatively small (and cash-strapped) site light NG.
Also, Geometry Dash has a whitelist system, so uploading someone else's songs to use in that game won't ever work. More details here: https://www.newgrounds.com/wiki/help-information/terms-of-use/audio-guidelines?path=/wiki/help-information/terms-of-use/audio-guidelines
If you genuinely hate NG for that then take a hike.
StickmanMarkinson
Was this song, yours to begin with? Were you uploading it for Geo Dash or for your own benefit?
Also they can't afford copyright, because they're not as huge as YouTube.