Games Workshop has released a statement to their Warhammer community website. In their statement, they put forth their stance against the kinds of people who are a little too into the Imperium of Man
Warhammer 40K takes place in an extremely dark satirical sci-fi setting where everyone is embroiled in a massive conflict and not a single side can be considered "the good guys." The Imperium of Man, often known for their Space Marines, is a fascist theocratic state that brings swift death to anyone or anything that contains even a perceived whiff of what they perceive as impurity. Everyone works in misery either in the battlefield or in the slums and manufoctorums dedicated to feeding the war machine. The rest of the major factions are just as bad, if not worse, but the Imperium is meant to signify "a cautionary tale of what could happen should the very worst of Humanity’s lust for power and extreme, unyielding xenophobia set in." Despite this, there are those who are worryingly on-board with what the Imperium represents and they "sometimes seek to claim intellectual properties for their own enjoyment, and to co-opt them for their own agendas."
In response to the hate groups that idolize the Imperium's philosophies, Games Workshop has a simple message:
“We believe in and support a community united by shared values of mutual kindness and respect. Our fantasy settings are grim and dark, but that is not a reflection of who we are or how we feel the real world should be. We will never accept nor condone any form of prejudice, hatred, or abuse in our company, or in the Warhammer hobby.”
The statement continues by flat-out saying that they don't want the money or participation of those who "behave to the contrary, including wearing the symbols of real-world hate groups." Games Workshop then speaks to their fans who run their own events, inviting them to join them in their anti-hate stance, offering to help those who need assistance running an event, including by making it a safe and rewarding experience for attendees. For educators, youth workers, and the leaders of young persons' groups, Games Workshop also offers assistance through Warhammer Alliance, an educational support program for those interested in Warhammer.