Weird Diodes inside RGB LED
Those diodes are there for ESD protection.
Since the red is more robust than the others (i.e. green and blue are more susceptible to ESD), green and blue have ESD protectors.
One may ask "how the G and the B can be more susceptible?" Well, the answer is "Because of InGaN". I cannot dive into details here but I can say that there are numerous researches about increasing the ESD handling of InGaN LEDs as it is a well-known problem.
The diodes are for protection from reverse current situations. But why only on green and blue? Those two have lower reverse breakdown voltages - judging from the spectral output listed on the data sheet they are both high output InGaN devices, which are much more sensitive than the red. In general the red LED chemistries have higher reverse breakdown voltages, much higher than the protection diodes.