Sorry for extra reply. To avoid misunderstanding, I would like to clarify that I do not just dislike but actually object tanking though I do not very strongly object.
I understand reasons explained by nikolgiorgos and don't disagree. But I don't want to group with tanking teams because many of these tanking teams perform inconsistently and disturb the real competitors of the league.
In last season, I blamed myself for not using all best players of my L23 Team to play against the bottom team in league at that time. This led to losing that match and eventually lost the league trophy. Though I don't want to mention the following as a reason for losing the league trophy, actually I was not too happy about that bottom team because it suddenly upgraded its starters in last few matches and won 4 or the last 5 matches.
Not all tanking teams decide to tank on very first day of the season. Not all tanking teams use similar 'weak' tactics and formations to play against all teams as far as they can manage. There is no code of conduct that players should be fair to all league opponents.
Sorry for arguing. If the discussion is limited to angle of tanking team, I fully believe tanking have more advantages than disadvantages to my team if I decide to do so.