When a national team wins, then it is the country's achievement. Something everyone in that country is proud of. The vast majority of people cheer for their national team and wants them to win.
In cs it is different. You dont have the same bonding to an org as you have to your country. Several orgs have had a lineup based around 1 specific country, but then completely change the whole roster. So if a roster that is centered around Brazilians wins a major, then the lineup changes to a swedish roster, then that major doesnt mean anything anymore.