1st Reason:
You need to separate the colour clothing from the white clothing because if they are washed together the white clothing will become off-white due to the colours released by the colour clothing during the washing.
2nd Reason:
We have dedicated washing programs for Cottons/ Synthetics/ Delicates/ Hand Wash/ Woolens/ Silk/ Bedding (option depends on the models selection) in the washing program knob. All the programs will have their own cycle of washing e.g. load size/ temperature/ spin speed and duration of washing for optimized washing performance. Therefore, if you are washing bath towels which are thick in texture and silk which is delicate and thin in texture, you cannot mix them to wash as the temperature/ spin speed/ duration of washing are different for best washing performance and to ensure optimal care for your precious laundry. The silk material which require delicate washing may risk being damaged if you wash under cotton program.