I understand Blizzard's thinking here, and I agree with it 100%.
Specifically, for those that are complaining here, on this forum, you had enough intelligence to come here and complain, so I will assume you have enough intelligence to either figure out how to make 100g easily, or have read enough posts by now to have learned. If you haven't, I will help you out.
I rolled an Undead Warlock. Quested my way out of the starting area in a matter of about 30 minutes. Flew to Undercity, trained mining, and walked around for about 45 minutes and gathered 5 stacks of copper ore.
Put the ore on the AH for 20g a stack (which was about a 5g undercut), and waited 15 minutes for it to sell, and waited to collect my gold. With quest reward gold, plus vendoring useless items, minus my flight to UC and AH fees, I made 97g, 44s, 29c in just under 2 hours, and most of that was waiting on my AH money to arrive. I could have sold the copper in trade and had my gold quicker, but that thought didn't occur to me until after I found myself waiting at the mailbox.
Of course, your server may vary a little, You may have to gather a couple extra stacks of ore to hit the 100g mark. You could also train herbalist and pick flowers while you are mining, and make a little extra as well.
Its not rocket science. If you say "but I wanna play how I want, and I don't want to mine/herb", then you are choosing to not participate in pet battles. If your RP idea of the game interferes with making some quick gold to pay for an optional perk of the game, then that is on you, not Blizz.