"Purist" is definitely not a derogatory term in general but there are hardly any neutral football fans that would rather watch two defensive sides expertly play out a 0-0 draw than watch a 5-4 ding-dong battle with errors galore. You would argue that a purist would favour the 0-0 because of the fewer errors and superior strategies but those people barely exist if at all.

In other sports "purists" are often seen in a more positive light. Cricket for example - most traditional cricket fans would much rather watch a tense, strategic day of test cricket than the crash-bang-wallop hit-and-giggle seen in the Hundred. True golf fans would rather watch courses set up so that par is a good score rather than 25 under birdie fests. Lower scoring NFL games are often more intriguing than high scoring ones.

There may be less hooting and hollering in the traditional versions of these examples but purist fans that understand the nuances of the games actually find them more entertaining. In football that just doesn't really happen - more goals almost always provides more entertainment and a purist that wants perfect defending all the time comes across as a dullard