That is certainly true as it applies to judging the religion, and really, when judging anything. How can a judgement be made on something that is not understood?
But there are multiple ways of looking at it.
There are also the angles of:
- What impact does growing Islamic influence have on politics
- Where is the concept of 'Islamophobia' coming from and how it is used in politics and why
- What impact does this have on our existing sociopolitical landscape
etc..
So while a greater understanding of the religion itself helps across the board, it isn't necessarily required to notice changes and impact, and then to try to determine if you are in favor or are against such things.
Understanding political language and how it used to mask political objectives applies to 'Islamophobia' and you don't need to understand Islam to have an understanding of this political tool / mechanism and what it might mean.
So really it depends on what aspect people are talking about.