A lot (and I mean a lot) of signs point to fighting them being a dangerous thing, including the fact that they have a red dragon. What reason do you have to be over by that bridge at the level you're at? There's literally nothing over there other than the creche as far as the game has told you. So you had to expect to run into some gith, and you know the gith are dangerous. The game signals as obviously that it can that you probably shouldn't expect to make friends, and Lae'zel gets treated like shit if you bring her along, too.
In any case there's a tiefling on the high ground that warns you about fighting them as well, so if you want to "logic" your way into setting that fight up I don't see why you couldn't say your backline decided to hang out up top where she was scouting in case something goes awry. I think that fight is ridiculously hard (it feels like a "your team but better" situation), but the player can make all manner of stupid decisions. You can aggro the entire goblin camp by deciding to kill the goblin that told you to kiss his feet. I've done it (and had to reload, lol). You can jump down a dark hole without feather fall and just die. Not having Lae'zel there, assuming you kept her, really makes encountering them a case of morbid curiosity, which is fine if you're out here scouring every corner of the map, but then "RP sense" is kind of out the window.
