Campaigner Alan Smart, 54, was recorded singing the lyric to the song which ends "have no got a home of your own?" as he held a placard against the UK Government's welfare reforms outside the event in Stirling last June.
There was a heavy police presence at the event, which Prime Minister David Cameron had attended.
But Mr Smart, a former head of current affairs at STV and who has also run broadcasting at the Scottish Parliament, was told yesterday by Stirling Sheriff Wyllie Robertson he had no case to answer.
Outside court, he said: "If the police had just asked me to stop I would have done. If they had told me it had made people feel uncomfortable I would have stopped.
"A few of the Tories who came out heard us, and they weren't offended. I think they even liked it as it was different to them being shouted at.
"In my opinion this was all about Stirling police. This was their big day with the Prime Minister up. They had all these controls in place and we turned up and did something they didn't expect."
He added that local officers from Police Scotland had to be seen to be "doing something." He added: "They arrested me 10 minutes before the conference was about to break, even though I had been there all morning. I don't know whose interests they were protecting."
The court had heard from a number of witnesses to the incident, which happened outside the Albert Halls in Stirling last June 7.
Mr Smart, 54, of Dollar, Clackmannanshire, who writes and sings under the name Citizen Smart, was recorded singing the lyric, "Go on home English Tories go on home, Have no got a home of your own?", to the tune of Irish rebel song Go On Home British Soldiers.
With the help of about 12 fellow protesters and an amplifier he went on: "For 300 years, We've fought you without fear. And we'll fight you for 300 more."
The court heard the song was sung numerous times over 30 minutes, causing Tory delegate Mark McIlfatrick and Stirling Council employee Christabel Wandless to speak to the police.
Mr Smart was arrested and charged with acting in a racially aggravated manner that caused or was intended to cause alarm and distress to the complainants and other people present.
It was also alleged his remarks would encourage others to do the same.
Giving evidence, Mrs Wandless, said: "It was uncomfortable. I'm English, I have lived in Scotland for 13 years.
"I have no problem with political opinions but I felt uncomfortable as a song like this makes it feel as though this is somewhere English people shouldn't be."
Mr McIlfatrick, an oil executive, told the court: "If you used any other race, say telling Polish to go back to Poland, or Indians go back to India, then you can't make those comments and this is also unacceptable."
Sheriff Robertson told Mr Smart: "I'm satisfied that in law there is no case to answer. We've lost the art of drawing the line, it seems to me. You're acquitted."