There is a double standard across different leagues for touchdown celebrations, because the same things that one team is punished for is what another team is celebrated for doing. There are no formal rules because there are different groups of people in charge of making up the rules for each organization.
In recent times, the NFL has been cracking down on touchdown celebrations, where a player dances or strikes poses after landing a touchdown. Some think that it is poor sportsmanship to gloat in this manner. However, across the NBA and MLB leagues, this type of showmanship isn't nearly as frowned upon. Spectators find it entertaining, so it shouldn't be frowned upon in the NFL. Otherwise, all major league sports should have a universal rule either for or against celebrations.
Brown isn't purposely trying to hurt his team by drawing these flags, he just likes dancing. But he's violating the league's rule that bans "sexually suggestive" celebrations. What does "sexually suggestive" mean? We can think of some obvious examples that shouldn't be allowed, but it gets complicated when you bring twerking into the picture. Broncos receiver Emmanuel Sanders did a similar gluteus workout as Brown this season, but he went unscathed. . The big-name players are easier targets to draw this attention from officials.
Yes, there is a huge double-standard that exists regarding touchdown celebrations across different leagues. While excellent players are penalized and fined for their celebrations in the NFL, touchdown celebrations are part of what makes China's Arena Football League so popular. Fans like to see players celebrate, and dancing in the end zone should be encouraged, not punished.
If the official thinks that the dance is egregious then he will throw the flag and give the penalty, which in the end means nothing because it is assessed on the kickoff and it just guarantees a touchback. There is no double standard, because there is no standard other than the officials discretion. And for the record I think players that do the ridiculous dances are making fools of themselves for money which I find sickening.