Adding to the other general advice here. People down-vote for numerous reasons.
- They don't like the content your answer
- They don't like you
- They don't think you structured your answer effectively.
- For the lulz
Don't take it personally, I've had controvertial posts where I've ben up-voted AND down-voted by scores of votes.
As I said in my other post, your answer came across as harsh. Tone is hard to convey across the internet, and people will read intent into what you post that you did not mean to convey.
So, while it takes a bit of effort, be as explicit in your answers as possible, and leave few things for people to assume. The whole "They are obviously bad at their job" in bold letters pretty much screams an accusation at people. When you post something strong, you can get a strong reaction to it.
Now, strong messages attract up-votes as well as down-votes, so it's up to you if you want to go that route.
If you're going to post in the tone of what you assume others would think, then you should phrase it with lead-ins like
- Well, it could be seen as..
- People may assume that...
- Some may think that...
- While I wouldn't take it this way, others might...
In other words, if this is not your viewpoint, disown the viewpoint by an intro to it. Take care to make sure that your tone isn't misunderstood or your intent.
By the way, I have HUGE problems with this myself, which is why I'm going into a bit of detail. Experience keeps a dear school.