Go to his Pokemon page, and if you click on 'more info' under each move it will show you strengths/weaknesses.
Basically, Bulldoze is pretty terrible. In some cases, giving up type bonus to gain advantage vs. common defensive weaknesses is worth it (like Poliwrath or Blastoise with Ice Beam to counter Grass/Flying/Dragon) or to open up a new type of Pokemon you can beat offensively (like Solar Beam on Parasect letting you crush Vapes and other Water 'Mons)
But....in Bulldoze's case....it's really neither.
You not only give up your type advantage to Grass, Bug, and Ice - arguably Fire's greatest value as an attacker - but Bulldoze is even weak to Grass and Bug! So you don't go just from 1.25x to 1.0x - you go from 1.25x to 0.8x.
To add insult to injury, what are you getting in return? Advantages vs. basically nothing worthwhile. Fire, Electric, Poison, and Rock.
On offense, every single Pokemon you'd gain an advantage against would either be weak to Fire anyway (Grass/Poison combos like venusaur/victreebell/vileplume) or is weak to water. So why make things hard on yourself when you can use any one of your 60 Pokemon with Water Gun?
The only exception are electric Pokemon but they're rare, weak, and rarely used as defenders.
On defense, the only possible 'surprise' effectiveness you open up is vs. Rock, which normally are super effective vs. Fire. So if someone goes after you with Golem/Rhydon/Omastar/Kabutops, you might surprise them. But let's be honest - 95% of ppl (conservatively) are going to be reaching for a Water Pokemon and not for Kabutops when they see Arcanine