No, actually, he was quite popular:
>Between 1970 and 1973, the Unidad Popular (Popular Unity)—the coalition of parties backing Allende—actually increased its vote, a growing popularity which in itself casts some doubt on the widely spread tales of economic disaster wrought by the government. In the last significant election, a fierce electoral battle for Congress in March 1973, the Unidad Popular increased its share of the vote to 44 percent. The rest of the vote was split among the several other parties, which at that time functioned freely and openly in the Chilean tradition. The 800,000 who greeted the President on September 4 constituted nearly one-tenth of the national population, the largest political rally ever held in Chile.
It was the upper classes that hated him, the people who had been getting fat off the people for the past several decades and stood the most to lose from his presidency.