From the White House to San Francisco police union headquarters, Colin Kaepernick's name came up as his decision to sit down during the US anthem reached far beyond the NFL. And many aren't thrilled with the San Francisco quarterback's strong words about why he is doing it: To instigate change and challenge authority when it comes to race relations and what he considers police brutality. Even his former coach, outspoken University of Michigan leader Jim Harbaugh, chimed in from afar in disagreement with Kaepernick's tactics — clarifying some earlier remarks that questioned the quarterback's motivation. "I apologize for misspeaking my true sentiments. To clarify, I support Colin's motivation. It's his method of action that I take exception to," Harbaugh posted on Twitter. A day after Kaepernick called Donald Trump "openly racist," the Republican presidential candidate fired back on Seattle's KIRO radio. "I have followed it, and I think it's personally not a good thing. I think it's a terrible thing," Trump said. "And you know, maybe he should find a country that works better for him. Let him try, it won't happen." Kaepernick, who has sat through the anthem for all three 49ers preseason games so far, is prepared to keep fighting for what he believes in, even alone. "The fact that it has blown up like this, it's a good thing. It brings awareness," Kaepernick said Sunday. "Now, people are really talking about it. Having conversations about how to make change. What's really going on in this country. And we can move forward. ... There is police brutality. People of color have been targeted by police." Martin Halloran, the San Francisco Police Officers Association president, sent a letter Monday to NFL Commissioner Roger Goodell and 49ers CEO Jed York denouncing Kaepernick's "ill-advised" statements and a "naiveté" and "total lack of sensitivity" toward police, along with an "incredible lack of knowledge" about officer-involved shootings. "There is some depth and some truth to what he was doing," Seahawks star Richard Sherman said of Kaepernick. "He could have picked a better platform and a better way to do it, but every day they say athletes are so robotic and do everything by the book, and then when somebody takes a stand like that, he gets his head chopped off." The police union invited Kaepernick or anyone else from the league to visit the San Francisco police academy to build communication and understanding about the profession. "In short, Mr. Kaepernick has embarrassed himself, the 49er organization, and the NFL based on a false narrative and misinformation that lacks any factual basis." At the US Open tennis in New York, top-ranked American John Isner spoke of Kaepernick after winning his first-round match. "I thought that was pathetic from him. The cause he was going for, fine by me — but don't do it in that fashion," Isner said. "For him doing it in that way really irked me. I'm a big Blaine Gabbert fan now." Gabbert and Kaepernick are competing to be San Francisco's starting quarterback. White House spokesman Josh Earnest said he was confident President Barack Obama was aware of Kaepernick's actions, but hadn't spoken directly with the president about it. "In general, what I can say is that I certainly don't share the views that Mr. Kaepernick expressed after the game in explaining his reasoning for his actions, but we surely would all acknowledge and even defend his right to express those views in the settings that he chooses," Earnest said. "That's what he's done, and even as objectionable as we find his perspective, he certainly is entitled to express it."