Hi, indicating preference can cause discrimination. To remain independant, unbiased, impartial shows you respect others choices and preferences even if they differ from your own.
Prefering one colour over another could cause upset or offense if negative comments were expressed without understanding. Asking why a colour, one that you'd not ordinarily select had been used is what gives an opportunity to understand choice, decision making and the reasons involved.
How you might do this would be personal

but could be in recognising ocassions where you would challenge an opinion/view based on your own personal preference. Professional practice is an environment that can enable us to know and understand how many views are beneficial for everyones knowledge, understanding & learning.
You could indicate that you agree with expressed opinion and then add your reservations, reasoning and explanations in reply. Impartiality - through body language, facial expression, spoken/signed language will show you appreciate how different backgrounds, cultural experiences, practices, thoughts and emotions can be.
To prevent discrimination or exclusion provide information that is understood by everyone.
You want services to be as easily accessible as possible so that administration & provision for children's care & learning, partnerships with parents, carers and stakeholders is as efficient and effective as possible.
Information that isn't understood causes confusion, misinterpretation and uncertainty.
Issues that affect the way in which information is provided will be unique to settings, but may possibly involve;
What information is provided and how - children's learning, activities, partnerships, associations, news, leaflets, verbal communications, welcoming or unwelcoming environment.
Methods of contact: use of technology - if a setting provides emailed newsletters but famillies have little or no internet connection they will not receive the same information.
Complaint procedures: if information is challenged how is it resolved - policy/procedure/news/alerts/feedback systems
The necessity or need to use others information: does information regarding campaigns, initiatives, learning fit with a setting's own approach.
Overcoming differences and phobia: knowledge of prejudice, discrimination, tolerance, perceptions, view and opinion.
Other barriers:
access - Parents that don't pick up/drop off may have difficulties obtaining information directly.
time - organising opportunities that invite everyone to attend/participate.
Time to research in order to provide sound, creditable up to date information.
language - providing information in a range of languages that help invite engagement & interest - issues could be accessing translation services.
Understanding, comprehension and use of the english language.
physical environment - display areas, possible deployment of staff.
training - understanding of the information, why and how to share.
funding for information: printing costs, skills regarding layout, design, content, administration, time, sourcing and management.
engagement: how do you invite interest so that information can be provided.
I'm sure there's much more, hope this helps a little
xx