When I think of a boycott, potential users of a good or service joining together and deciding not to use that service. So for instance, a group of people boycotting a baker who refuses to make a cake for a gay couple. Without question, this can raise awareness (of the baker's bigotry) and potentially change the baker's stance, or put him/her out of business altogether. This absolutely can work.
When I think of a strike, I think of labor unions or a group of employees fighting for their rights as employees. They want better pay, hours, or something to that extent.
I'm trying to understand how basketball players are in either of these categories. If its the second category, maybe they are "striking" to force owners to donate to social justice movements? Seems strange, since that hasn't been the message so far. Also, players could do this themselves (donate time, money, etc.). Or they are they are "striking" against consumers of their product? "Striking" against police departments? It's not really the same thing.
Maybe this all happened so quick that the players themselves are still trying to figure out what they are trying to accomplish. Maybe it will lead to something positive, but I'm still trying to understand it, personally.
