I wonder if ancient homo line lost their fur because fur catches on fire too easily.

Edit: This article is quite poorly written. The only thing it says is that humans seems to have an adaptation to recover from burn wounds better/faster than apes.

There's always a possibility that cave men who constantly had huge clouds of smoke all the time in their caves ended up all dying off except the few who were resistant to such toxic smoke. Who were the only ones to pass on their genes from that point.

Meanwhile in other places where the smoke was not so thick it didn't make any difference to the ones whom the genes were passed on to.