Not to defend childish Twitter name-calling, but the reason he did it was that the dude picked a pointless fight with him first. Let he who has not escalated an insult battle throw the first stone.
Your sentence is a a classic example where everything after the "but" pretty much contradicts what came before it.
No, they are addressing two different things. The second half addresses the parent assertion that he did it simply out of spite over whose cave rescue solution worked out first.
You may not be personally deafening him, but you are certainly offering a possible defense. So while you say "Not to defend childish Twitter name-calling" , you are also offering a possible defense for someone calling another person a pedophile without cause.