Do you know, or do you believe? What do you believe that they are ineffective at??
The reality was that in March, there was never any Level 1 medical evidence of the percentage of effectiveness of masks in preventing spread of virus. That means there were no double-blind randomized control trials, with a crossover arm that definitively stated masks were better than no mask. Its a tool in making evidence based medical decisions and recommendations.
There are retrospective studies, single arm studies, anecdotal evidence that shows a mask it better than no mask. Also, its just plain common sense.
The unfortunate part of the entire masks-no mask debate is that many people make up their mind first, then look for evidence to support their position. Looking at and trying to understand medical studies isnt factoring in their opinions.
As for the NFL and Ravens screwing anybody. The NFL likely doesn't have good impartial medical advisers and hasnt filtered down information on infection prevention practices. They likely put some practices in place to satisfy some guidelines and then get games going so they can start the money making machine rolling. This shouldn't be a blame game, with flinger pointing, but a lot of people feel that in order for them to be right, somebody else has to be wrong. Its just the situation of playing a contact sport during a pandemic.