Last Ranked (placement) rant

Champion select goes fairly well, so I lower my defenses (bad choice) and stay relaxed.

After some kill trades I notice that Ashe died because wandering in an unwarded river by herself looking for 3 ppl (one of which) was low hp. I was retreating because I was oom just to read this:

Ashe: we lose

We were 1-2 kills lower at that point, nothing that couldn't be climbed back but that attitude pissed me off so I replied:

Xerath (me): If you keep doing that yes

Ashe: lol noob

And then she (note, referring tot he character, I have no idea of the player's gender) keep pushing alone in her lane getitng killed multiple times, I tell her in return (each time) to stop pushing alone. Nothing more nothing less, I didn't try to be comforting nor to be angry at her. All I got in return was Malphite telling me to stop flaming and Ashe keeping the "lol noob" behavior.

Now tell me why shouldn't I get pissed off when not only I'm made the bad guy out of there but also Ashe doesn't quit that stupid attitude.