Leader of the British National Party Nick Griffin and activist Mark Collett claimed a victory for free speech after walking free from Leeds Crown Court.
A campaign group described the BNP's views as "abhorrent"
Mr Griffin, who uncorked champagne in front of supporters, said the jury were "decent Yorkshire men and women" who had "seen common sense".
Prosecutors were forced to defend their decision to bring the pair to trial.
And campaign group United Against Fascism described the acquittal as "a travesty of justice".
Sabby Dhalu, the organisation's joint secretary, said: "We think that the BNP does indeed incite racial hatred.
"In areas where the BNP target, racist attacks have been proven to increase."
Ms Dhalu said the majority of society found the BNP's "fascist and race-hate views abhorrent".
"We will alert them to the electoral threat the BNP poses and encourage them to vote against them in the next election."
Outside court after the acquittal, Nick Griffin said West Yorkshire Police should have spent their time and money hunting down Islamist extremists rather than prosecuting him and Mr Collett.
He said: "This party is now an icon of resistance to the forcibly imposed multi-cultural experiment which has failed."
He then told reporters he would choose his words carefully in future.
He said: "I always choose my words carefully . . .but I will continue to choose my words very carefully indeed, I don't want to go back into the dock unless I have to."
The Crown Prosecution Service (CPS) defended its decision to proceed with the case.
CPS lawyer Helen Allen said: "This prosecution sends out a very strong signal that where the CPS believes someone has tried to incite racial hatred, we will treat it with the utmost seriousness and will not hesitate to prosecute robustly."
The BNP has seen its popularity rise - which they attribute in part to the publicity generated by the court case.
The party has more than 40 council seats and became the second-biggest group on Barking and Dagenham Council in east London in an election earlier this year.