One can support / love / be loyal to an entity but that is not to say you have to go round in a permanent state of happiness. That would be utterly naïve in respect of understanding human emotions.
In fact it would probably make you an imbecile.
And to be honest coming out with tosh like that in such a simplistic black & white way belies the truth behind what is a football supporter in as much a way as the behaviour you are criticising.