Embarrass isn't the right word.... but each club's kit is a fundamental part of it's identity.
Liverpool, those red shirts.
Chelsea, Blue.
Newcastle, barcodes
When a side adopts something different, it can take you aback. Gillingham in Red with blue trim this year. Arsenal when they adopted the Burgandy shirts. Usually there is a historic precedent but either way. It's different and contrary to paradigm and convention, it is an affront to identity. When there is seemingly no reason for it, it's just not on.