For "boycott" to be at all meaningful, there has to be a distinction between
a) Not buying a product or service because you are not interested or there are cheaper/higher quality alternatives, or whatever.
b) Not buying because you want to penalise the business for a practice you dislike, that doesn't directly affect your experience when using their product or service.
The first is the default reason we don't buy most of the things we don't buy. The second is a boycott. If they were the same thing, they probably wouldn't have needed to invent a new word for it.