rationalskepticism.org

The basic rule is this : you can attack an ideology as much as you like but you do not attack its followers
Ideologies have very thick skins so what you say about them will not affect them at all
Their followers though are human so are therefore more susceptible to being attacked

By attack I mean legitimate criticism although how individuals critique an ideology is entirely up to them
And so you can legitimately attack Islam without simultaneously attacking Muslims also
Sadly not everyone understands this subtle distinction or even thinks it actually matters

This also applies to criticism of Israel which is the other go to example of this
For criticising the Israeli Government is not at all equivalent to anti Semitism

Very often it works both ways and sometimes simultaneously too :

criticism of the ideology will be presented as simple prejudice / discrimination when it is actually perfectly legitimate
criticism of the ideology will be presented as perfectly legitimate when it is actually simple prejudice / discrimination

Question the motivation of your critics and you are under no obligation to pay attention to anything they say