Bill Ackman wants you to know exactly why he's been stirring the anti-vaccine pot all weekend

• Bill Ackman wants people to know that he is "not an anti-vaxxer."
• He's offering to fork out $150,000 for scientist Peter Hotez to debate Robert F. Kennedy Jr. on the topic of vaccines.
• "This is a debate that you cannot walk away from," Ackman tweeted at Hotez.

Billionaire investor Bill Ackman, who's spent a good chunk of the weekend putting his weight — and his money — behind the prospect of a Joe Rogan-hosted vaccine debate, wants you to know he's not an anti-vaxxer or an advocate for conspiracy theories.

It all started when vaccine scientist Peter Hotez tweeted in support of a Vice article published on Friday that criticized both Rogan and his podcast guest, the known conspiracy theorist and presidential candidate Robert F. Kennedy.

Rogan got mad at the article — and Hotez — and called for the scientist to debate Kennedy on his podcast, "The Joe Rogan Experience." Now the situation has turned into a full-blown Twitter firestorm, with everyone from Elon Musk to Ackman weighing in on whether or not Hotez should debate Kennedy.

"I am not part of the gang of three, but I strongly believe that an open long-form debate on vaccines with you and @RobertKennedyJr moderated by @joerogan would enable the public to better understand these issues," Ackman tweeted on Saturday night. The Pershing Square CEO was referring to Musk, Kennedy, and Rogan — whom Hotez called out on Twitter and MSNBC on Sunday for tag-teaming and dogpiling on him.

Ackman further questioned why Hotez would "say no" to an on-air debate on vaccine efficacy, considering he and Rogan were offering $250,000 in donations to a charity of Hotez's choice if the debate happens. Rogan proposed the initial sum of $100,000 on Saturday, and Ackman offered an additional $150,000 less than two hours later.

Ackman also goaded Hotez, saying that by refusing to debate his "antagonist" in a "public forum," Hotez was handing an "uncontested victory" to Kennedy.

"If you are truly interested in saving lives, you need to further the public's understanding of the truth about vaccines," Ackman added. "This is a debate that you cannot walk away from. It will be watched by millions. I write from the perspective of three jabs and my fully vaccinated children."

Since Friday — the day the Twitter drama started snowballing — Ackman has tweeted at least seven times about the topic. At one point on Sunday, Ackman wrote that he thought a scientist-versus-political scion showdown on Rogan's show would help "advance the discussion in pursuit of the truth."

He did not specify what he thinks the "truth" could be, where vaccines are concerned — but ended off his latest tweet as of press time by saying he isn't against vaccines or the people who make and take them.

"In an effort to get to the truth, I try to keep my mind open to alternative possibilities and weigh them against each other," Ackman wrote on Sunday evening. "I often find that truth can emerge when two or more articulate and intelligent individuals in an open forum discuss and debate a controversial subject and are required to address unscripted questions from a knowledgeable audience or moderator." 

"In getting to the truth, I want to hear from the greatest skeptics and advocates. Both deserve a platform on the path to truth. And no, I am not an anti-vaxxer," he added.

Ackman has on at least one notable occasion been vocal about his support for vaccines.

On January 5, 2021, he tweeted that the US should "launch mass vaccinations" of the elderly as soon as possible. He added that failing to vaccinate people sounded "like genocide," brought about due to "a failure of logistics and mismanagement."

"There is no excuse for inadequate supplies. Use the Defense Production Act if necessary. Every day we wait, thousands more will die," Ackman tweeted at the time. "If .@elonmusk can deliver 500k Teslas and .@JeffBezos can provide same-hour delivery, we can vaccinate every American. The time is now!"

Representatives for Ackman at Pershing Square did not immediately respond to Insider's request for comment sent outside regular business hours.