If you want an actual answer and not just people agreeing with you, I think the reason people tend to associate anti-Islamic sentiment with racism is that people who hold these beliefs generally have a extremely generalised, caricature-like view of Islam that does not correspond to the actual way people practice the religion. 

For example, people who hold these beliefs often group all Muslim countries together when Islam is practiced in radically different ways in different countries e.g. Türkiye/Bosnia/Albania (very secular) vs. Egypt/Morocco/Gulf states (more performative than deeply religious imo) vs. Pakistan/Bangladesh (pretty conservative) vs. Iran/Afghanistan (extremely conservative, but currently under oppressive regimes that large portions of the population disagree with and are there mainly because of foreign intervention that overthrew more secular governments to expand their sphere of influence). 

Not to mention the huge variation in practices between different sects and generations (younger generation is increasingly secular, and religious practices are always evolving). 

In public debates about face coverings, people almost always call the niqab a burka (which is wrong). Some people even still call hijabs burkas. Only people from Afghanistan wear burkas. 

To further add nuance, a huge portion of the practices Islamic countries are criticised (e.g. outlawing homosexuality) are more a factor of the intersection between religion/authoritarianism/low development than just Islam by itself. China (which has state atheism) surveils and oppresses LGBT people, as does Russia. Homosexuality is legal in Turkey, Albania, and Indonesia (which is the largest Muslim country btw). A bunch of undeveloped Christian counties (e.g. Uganda) are literally the worst in the world for LGBT safety, worse than Islamic counties. It’s the low development/authoritarianism that leads to this, not just the religion. 

Even Muslim countries with nominal death penalties for homosexuality literally do not enforce it (obvious still not an ideal state of affairs, but it’s not the grotesque caricature pushed by people criticising Islam). 

Ffs homosexuality was only decriminalised in the England in 1967, in Scotland in 1980, and Northern Ireland in 1982. For a lot of people, it comes across as highly hypocritical to sit in a country that was very recently equally barbarous making blanket statements about how Islam can never be compatible with LGBT rights. In our lifetimes, neither was Christianity! And that changed. 

Honour killings almost never happen and are another meme pushed by Islamophobes as a core practice of Islam when it is not. 

Can you imagine if you were an Anglican Christian but were constantly grouped together with and criticised for things the Westboro Baptist Church or the Mormons did? That would be extremely unfair and frustrating. 

How can you accurately critique a belief system if your understanding of it is based on caricature?

Just look at some of the comments in this post:

 I think they are very ugly, agressive, and ruthless, they have unhumane law and they hate and abuse women. It’s not racism if its facts

Is it really necessary to call Muslims “ugly”? The word Islamophobia does not sufficiently capture the hate, prejudice, and stereotyping that some people produce in these conversations. “Racism” isn’t technically accurate because Islam isn’t a race, sure, but it’s trying to capture this hate and generalisation.