According to soccer's Laws of the Game, Law 04, Section 5,
“Equipment must not have any political, religious or personal slogans, statements or images.”
In the Laws of the Game, Law 04, Section 5, the definition of political includes that “slogans, statements or images related to...any specific political act / event” ... "are not permitted."
When the U.S. Soccer Federation used the LGBT rainbow on the kit in June 2017 and June 2018. U.S. Soccer said the purpose of their rainbow jerseys was “to celebrate LGBTQ Pride month.” Also, the Football Association of Ireland's LGBT rainbow jersey in June 2018 was used in the month of June specially for pride month.
Pride month is observed by LGBT advocates each year in June in order to advocate for political policies supporting their causes. When soccer events use the LGBT rainbow, especially in the month of June, they are making a political statement. As Leana Garfield of Business Insider explained, “Pride is a month-long LGBT+ celebration, protest, and act of political activism in the U.S.” German Lopez of Vox says, “LGBTQ Pride Month is now a mix of celebration, protest, and political activism.” A Brazilian leader described participation in a São Paulo Pride March as “a political act, an act of resistance.”40 On the homepage for Slovenia’s 2018 Pride March in Ljubljana, march organizer Nina Perger specifically emphasized that in Pride Month “political message[s are] unavoidably intertwined.”
U.S. Soccer stated that this political event was their reason for placing the LGBT rainbow on the U.S. national jerseys in June in 2017 and 2018. In 2017, the U.S. Soccer Federation explained that the purpose of the LGBTQ rainbow jerseys was “to support LGBTQ Pride Month,” “in recognition of LGBTQ Pride month in June,” and that the rainbow numbers were “pride-inspired.” In 2018, U.S. Soccer stated that the purpose of the rainbow jerseys was “to support LGBTQ Pride Month” and “to celebrate LGBTQ Pride Month this June.” The U.S. Men’s National Team also cited a “pride-inspired” decision to wear the rainbow on their jerseys to “celebrate Pride month” and “in recognition of LGBTQ Pride Month.”
The Football Association of Ireland announced they would require players to wear the LGBT rainbow on their jerseys for the month of June, i.e. “pride month,” saying: “The back of match kit. Not just a number, this is a statement. Ireland, supporting #LGBT rights.”
Violation: This use of the LGBT rainbow by both the U.S. Soccer Federation and the Football Association of Ireland specifically in observance of an annual political event, i.e. “Pride month,” violates the ban in soccer's laws of the game on "slogans, statements and images" in observance of any specific political act / event”