They can be both, but in many of the listed countries there aren't really Amazon workers (at least not warehouse staff), and they are not "[striking] for better

They can be both, but in many of the listed countries there aren't really Amazon workers (at least not warehouse staff), and they are not "[striking] for better working conditions" as stated in the headline. That is part of the #MakeAmazonPay movement, but it's not all the movement is, and saying that employees are striking in 20 countries is completely false.