That's extremely subjective, but I'd rather save that $14 a month towards retirement. And if YouTube was only available with ads... well, that's no videos for me, maybe for the better, I would waste less time.
In high school I knew a kid who would go around looting loose change from unlocked cars. He'd pull the driver side door open like it was his car, hop in, loot the center console, then hop out like nothing happened. He wouldn't take valuables (as far as I knew), just change, so maybe a few bucks per car.
His rationale? "Nobody will cry over a few missing quarters and they are free to lock their doors anyway."
The reason it's not stealing is because the cost to the serve content is tiny (spare change) and the sites don't stop you from viewing it with ad-blocker (unlocked doors).
1. Save $14 for retirement and not watch Youtube
2. Save $14 for retirement and watch Youtube with ads
3. Pay $14 a month for Youtube without ads
The only option that's not fair is expecting private companies and creators to give you entertainment and its delivery with nothing in return