"We just can't understand this racist label pinned on us through no fault of our own," he told Malaysiakini.
"People who say that we are racists should first examine the meaning and definition of the term," added the Hindraf leader who is on self-imposed exile in London.
Waythamoorthy was responding to an avalanche of public comments against him.
This followed mostly calls in Sabah and Sarawak that PKR supremo Anwar Ibrahim should re-assess his position in the party. Waythamoorthy was quoted in the article as well.
He reiterated his charge that Umno has over the past half-century finally degenerated into a racist organisation.
But he disagreed with the assertion that Hindraf and Umno are similar or that it is a case of "the pot calling the kettle black".
"A racist is one who denies other people their place in the sun and their legitimate rights under the Federal Constitution. That's Umno. That's the truth whether some people like it or not.
"A person fighting for his place in the sun and his rights under the Federal Constitution – read Hindraf – cannot by any stretch of the imagination be labeled racist. That would be defamation," he stressed.
The Hindraf view is that Umno has in fact emerged as the single greatest threat to the security of Malaysia "because of the irresponsible and infantile manner in which they conduct their politics".
He cited the lingering 'Allah' controversy as an example.
Only Indian issues
The Hindraf chair also readily admitted that he only talks about Malaysians of Indian-origin all the time and their issues.
However, Waythamoorthy sees nothing wrong with this approach "since we are in line with the Declaration of the Rights of Persons Belonging to National or Ethnic, Religious and Linguistic Minorities adopted as Resolution 47/135 by the UN General Assembly on Dec 18, 1992".
He claimed that if he and his brother Uthayakumar do not speak up on Indian issues as human rights lawyers, "no one else in Malaysia will".
Uthayakumar, the elder brother of Waythamoorthy, is the pro-tem president of the Human Rights Party (HRP).
While dismissing MIC as a party led by a "bunch of self-serving sycophants", Waythamoorthy also claimed that Pakatan's Indian reps have been barred from raising issues concerning the community "for fear that they will show up Pakatan as being ineffective and antagonize the non-Indians".
"I am an Indian. I know only Indian issues and no one is taking up their cause," he reiterated on what "is good enough for him."
"I know that other Malaysians are also being systematically marginalised as well by the system. It's not my business to speak up for them," he said.
'Examine your conscience'
The Hindraf chair again stressed that he has done his part for other Malaysians by arranging a briefing on the Malaysia Agreement at the House of Commons in London on March 9.
The delegation of other Malaysians to the briefing is expected to be led by Jeffrey Kitingan who, among others, heads the Borneo Forum, an NGO.
Elsewhere, Waythamoorthy has also made contacts with the British Prime Minister's Office, the Foreign and Commonwealth Office and the Commonwealth Secretariat to bring the plight of Sabah and Sarawak to world attention.
He also hopes to help East Malaysian states at the European Parliament, the US State Department and the United Nations just as he has done for Hindraf.
"We have been reaching out to other Malaysians in our own way although we are very busy pushing our own case worldwide.
"If I am a racist, surely I won't lift even a finger to help others fight for their place in the sun," he said.