BN suffered its worst ever result in Saturday's polls, losing its two-thirds majority in parliament for the first time since 1969 and conceding four more states to a resurgent opposition.
Abdullah was punished over rising crime and inflation in an election also tinged by rising racial tensions between majority Muslim Malays and minority ethnic Chinese and Indians.
"I think the people must have been very angry, all the races, Chinese, Malays and Indians," Mahathir said.
"The problem is we (the government) have become so arrogant. We suppress any opinion that we do not like and they begin to believe in their own reports which are not actually consistent with what is happening in the country."
Abdullah was Mahathir's hand-picked successor when he stepped down, but after the new leader dumped several of his pet projects he began launching accusations of economic mismanagement, nepotism and corruption.