It's unfortunate, but the current state of copyright law is tilted wildly in the copyright holder's favor. The copyright holder has the right to get your content pulled merely if they claim you're infringing their IP. The burden of proof is then upon you to show that you aren't or your use is protected by fair use (guilty until proven innocent). Which in the case of deliberate use like a background music snippet for a YouTube video would probably involve going to court. (If it were incidental like a car driving by with a song playing on the radio, you could point that out to YouTube in your DMCA response, and a real person would see how that's obviously not infringement and reinstate your video.)
Even if you pay the copyright holder for a license, that's not a guarantee your video won't be pulled. They use computer algorithms which scour videos for sound clips which match their IP, and hand a big list of "infringing" videos to YouTube with a DMCA request to pull them. All licensing the music would do is give you an easy out in your DMCA response - provide proof that you've licensed the music. Your video would still be pulled (or the sound muted) until the DMCA request and response process was completed.
Even if you don't plan to monetize your videos, if the music copyright holder files a DMCA takedown request, it can end up in them getting all the ad revenue for your video. Then one day you happen to get a viral hit with tens of millions of views worth thousands of dollars in ad revenue. And instead of being able to collect on that, the money will automatically go to the music copyright holder unless you fight them in court.
Just don't use copyrighted music. There are lots of talented people out there. Find a musician (or even wannabe musician) and make your own music. Or use music tracks that aren't encumbered by copyright.