Speaking at a WADA symposium in London yesterday, Reedie complained that his organisation's yearly budget of USD 30 million (26.5 million euros) was potentially less than Sharapova's annual earnings.
But that brought a furious rebuke from Haggerty.
"The statement made today by the WADA president is unprofessional," said the attorney in a statement.
"Justice, whether in the eyes of WADA or a court, must be blind, including being blind to a player's earnings.
"Mr. Reedie owes an apology to Maria and to all successful tennis players unless he wants fans to think WADA has different standards for players depending on their ranking and earnings."
The 29-year-old has vowed to contest her ban at the Court of Arbitration for Sport.
Reedie said that WADA was punching above its weight due to its limited budget but suggested that it was a satisfaction to have caught Sharapova despite her potential to earn more than that in a year.