Yeah, he/she did explained but the reason is not technically justified for example image's resolution, system's user friendly etc. which the other brand also fulfilled.
The intentions is not to burden the end user which they have to put a lot of effort in fighting for the brand that they wants. It is more on contractual requirement and process. We do have an agreement (fixed price) and list of approved brand we can choose and propose.
My actual point is end user may need to give a chance for other brands to be selected. If there were a huge gap between two brands, I am understand but with the reason of "not familiar using this brand" is for me not fair. Training and support can be provided. It seems like, if I am a doctor and well trained with brand A, i don't care with other brand which for me may lead in monopoly.