Religion should not be a protected characteristic.
I do agree with you. Religion and ethnicity are two different things so it does my head in when someone claims anti-Islam sentiment is racist. Factual definition says it's not, that's
secterianism because Muslims aren't a race, but a diverse religious group. Even to the point where the political leaderships of the Sunnis and Shias generally despise one another. Two different things altogether. If someone would say that bashing Christians is racism everyone would understand said argument and agree that Christians aren't a race. The Jews were racialized by a complete lunatic who overlooked ethnic differences between different people but the larger the religion is, the more impossible it is to do that.
I'll take your argument a step further though. Freedom
from religion is more important than Freedom of religion. Secularism is non-negotiable and religious sects should be able to be shut down by the government if they violate secular norms in society. Even if it means pre-crime detention of people trying to undermine secularism. I also believe education should actively encourage irreligion. Mainly, this approach is to protect people who get preyed upon by religious zealots already as toddlers to make them as secular as possible after they've been to school.
The religion part of the US first amendment is basically a suicide pact since it has allowed Christian fundamentalists to wreak havoc for centuries. Being vigilant against religious extremism is the only way democracies can sustain in the long run because the biggest nutcases will always brainwash their kids the hardest and will have a lot of them. Doesn't matter what religion, it's the same mentality of dogmatism towards anyone who doesn't believe sky daddy runs everything. If god would exist, it's almost certainly at a frequency where it doesn't have time for us, the same way that the solar system is heliocentric. That's why I'm a committed agnostic because it's a case of 'don't know, don't care'.