They're a private company who is free to do what they want, and the people complaining are private individuals who are free to do what they want. There's no assault on anyone's liberty in either direction. Companies can freely modify their products, and customers are free to be pissed off when they do. In this case, people feel that YT is removing dislikes to prevent PR damage to brands and individuals who post unpopular videos on their website. They think Google is prioritizing its profits at the expense of their product. Let them complain.