How so? The wording is pretty clear. Once your character has an attack value, it doesn't matter if it came from a weapon, a spell, a hero power or any of those (a weapon granted by a hero power!), it's your character doing the targeting and attacking.
If this weren't the case, it would be incredibly more confusing by the way: is that 1/2 minion that you just buffed with a +1 attack spell to a 2/2 allowed to attack the faerie dragon and kill it? Arguments could be made for both cases. (and even for making it deal 1 damage instead of 2!)
Fluorescent - Fluo - currently retired, playing other stuff
i5-4670k @ 4.5 / Thermalright Silver Arrow Extreme / Gigabyte Z87X-D3H / 8GB DDR3-1600 RAM / Gigabyte GTX 760
And for what it's worth, Hunters.
It's as clear as possible without an essay typed out there. It can not be targeted by spells and hero abilities. Battlecry is not a spell. Deathrattle is not a spell. Swinging with a minion is not a spell. Swinging with the hero's attack is not a spell, no matter how that attack was obtained. You do not pick a target for board-wide damage. You do not pick a target for random effects. You can not target it with Explosive Shot, but Explosive Shot can target an adjacent minion. You can not target it with Cone of Cold, but Cone of Cold can target an adjacent minion. You can not target it with Betrayal, but Betrayal can target an adjacent minion.
It's all perfectly clear. -.-