It's hard for this case. It is a crossover of two different guidelines - one which says "punish people for verbal abuse" and the other is "try to see if the abuse was one-sided". In this case, the non-reported player's verbal abuse was far worse than that of the reported player. Although the guidelines for Tribunal say that you should focus on the actions of the reported player, on balance this player got a real time of it from that enemy - and therefore I can see why people sympathised and pardoned.
I would also say that I would have probably voted to pardon too - not because I sympathised with the reported player (I don't, I feel that you need to have self-control in a game to not react - and that just because someone is verbally abusing you doesn't give you the right to abuse them back) - but because it's a 1-Game case. With no other games to base my judgement on, I'd have either carefully re-read the chatlog or voted to skip. 80% chance I'd have skipped.
Regarding online translators - don't rely on them in cases where most of the chatlog is in another language, but they certainly can be useful to translate single words or phrases so you can get an idea about what is being said and whether it's likely to be offensive in nature or not. The Tribunal guidelines state to skip cases where the chatlog is in a language you do not read.