Why is everyone picking on Bill Ackman these days?

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Bill Ackman

At first glance, 6-foot 3-inch Bill Ackman is not the kind of guy you would peg as a target for the schoolyard bullies, but that's pretty much what he has become.

Described a few months ago in Vanity Fair by famed business author William Cohan as "Tall, athletic, handsome with cerulean eyes," the fabulously wealthy head of Pershing Square Capital Management has looked notoriously small.

He has been thrashed in the marketplace by fellow activist investor Carl Icahn, watched his huge stake in JCPenney stumble, and in general finds himself targeted by other hedge fund giants who now see his moves as contrarian plays rather than investments to emulate.

Consider the events of Wednesday alone.

News came out before trading that he was making his biggest bet yet, on Air Products and Chemicals, in which he was taking a 9.8 percent, $2.2 billion stake. Shares rose in concert with the announcement.

(Read More: Activist investor Ackman makes his biggest bet ever

Soon after, though, things got bad.

George Soros said he was making a huge wager on Herbalife, the company that Ackman has likened to a pyramid scheme and on which he has a short position. The Soros news sent Herbalife shares soaring.

That came a week after Wall Street was abuzz with a bitter slam against Ackman that came courtesy of fellow hedge fund hotshot Dan Loeb, of ThirdPoint.

Loeb had posted a Bloomberg terminal taunt that read:

New HLF product: The Herbalife Enema, administered by Uncle Carl.

Icahn already had taken on Ackman regarding Herbalife, and the two famously engaged in a bruising verbal brawl on CNBC's "Fast Money Halftime Report" back in January.

(A look back: Icahn, Ackman in epic showdown)

Indeed, these are not fun times to be Bill Ackman.

As Forbes reported:

This is a nightmare situation for Ackman's Pershing Square hedge fund, which has put on a massive short on Herbalife's stock that is in the $1 billion range, betting that the shares of the company would fall. It remains possible that Ackman's investment thesis will be proven right and regulators will deal Herbalife a death-blow and deem the company a pyramid scheme, but so far Ackman's bet has hurt him this year.

Later in the day, JCPenney shares tumbled on a New York Post report that CIT Group has halted its support for deliveries from small manufacturers to the company's stores.

Penney shares did recover Thursday morning after the company said the Post report was in error.

But it remained striking just how much Ackman, whose representative did not respond to a request for comment, remains in the market crosshairs.

(Read more: Ackman to CNBC: Haven't covered Herbalife short)

It's worth nothing that Ackman's portfolio has performed well on a broader basis, with Procter & Gamble in particular reporting solid earningsThursday morning that pushed shares higher.

But he remains Wall Street's favorite schoolyard target.

And as often happens on schoolyards, there are always those ready to pile on.

Robert Chapman, founder of Chapman Capital, was there to help out in a CNBC interview Wednesday during which he also defended Herbalife and ridiculed Ackman.

CNBC.com reported:

"I'm going to take a page out of Carl Icahn's book here, so I owe him for a little plagiarism here," (Chapman) said. "Making money in a stock is a lot of fun. Making money when Bill Ackman's losing money is like a ride in the circus. It really is the cherry on top of the sundae."

Chapman added that anti-Ackman sentiment wasn't the driver.

"I think people that put capital at risk in their portfolios are doing so for capital gains, and they want risk-adjusted gains," he said. "But when someone as sanctimonious as Bill Ackman tries to put Herbalife out of business, and I can make money—double, triple, 10 times my money over a long period of time—while he's not covering a single share, that's kind of like Christmas every month."

—By CNBC's Jeff Cox. Follow him @JeffCoxCNBCcom on Twitter.