Currently we're using youtube API to get dislikes count ...so they just hid it from the user, and the actual number is still there if you know where to look? That's surprising.
Probably they will either begin at some point to return the value “0” for dislike count for others than the uploader at some point or if not they will probably freeze the value at its current. Maybe it’s already frozen. Did anyone try to see if the number is changing as seen publicly by one account when new dislikes are added by other accounts?