In CS, another sin is that you have to "justify" the significance of the results even in theory conferences.

Hence many papers contain exaggerated claims with respect to practicality, importance and so on.

Another sin is that the results need to be "difficult" and "surprising" in order to publish. Hence, if you present your story in a simple-to-understand fashion, you run a high risk of rejection. Better not simplify your results before publishing -- keep all original notation, even if you figured out you do not need that many indices.

This has become a dogma and there is little chance of all this nonsense stopping anytime soon.

It is refreshing to read old papers that merely get to the point and are significant while being nice to read.