You make a good point, given that you should be able to question when something you are paying for does not behave according to what you were lead to expect.
However, if I walk into the place I bought my faulty TV and grab the guy by the scruff of the neck and yell at him about "What the heck is he doing, and why the heck haven't I gotten what I paid for" I am a jerk, and should not conduct myself that way.
We only have these forums to communicate with the people who make the game that we enjoy. They are doing a job, and trying to pin down these bugs...do you think they'll enjoy their job more if we treat them however we like?
Or should we maybe ask questions in a calm and collected manner and provide all the information we can, so they can get things done in a more orderly fashion?
Ok we are straying from the topic somewhat here but I will elucidate. To take the analogy further, when something that you have been complaining about continues to malfunction despite numerous polite requests it is only natural that customers will become frustrated with the manufacturer. Forums all over the internet are filled with angry posts because that's just the way the world works - these forums are a means of communication created by the manufacturer precisely so the customer has a direct line to the developer/manufacturer.
Sometimes you have to write an angry post or two just to communicate that you are unhappy with the situation, just as sometimes politeness is the better course of action. Both have their place and to be honest the amount of annoying bugs in this game (lag, boss fights etc) plus the utter lack of cohesion in others (gear itemisation being the most blatant example) and BW's frequent inappropriate responses, or lack thereof, merits an angry post or 10.
So all things considered I don't think the tone of the OP's post is unwarranted given how long this game has suffered from one (or several) variety/ies of encounter-breaking bug/s or another. The fact that the CS rep has responded to this thread is encouraging but ultimately doesn't really mean anything beyond the fact that they were unaware of the issue having presumably missed it during testing. Not encouraging.