It’s not just in their head.
What, you don’t know a single holder-than-thou person who takes your words out of context even as you utter them? I have a few in my social circles. Let me give you an example from where they corrected themselves:
Them: So she needs to get a job now. Though I don’t mean to say she doesn’t have a job already, because being a mother and homemaker is valid work which needs to be respected –
Me: Yes yes, so say we all. You mean she’s seeking paid employment. We get it.
I’m sure I sound like an impatient ass in that exchange, but let’s look at what’s happening. They are stating something they know we are all already aware of and agree with (that homemaking and parenting are valid work that should be respected – that’s been discussed in this social circle several times, and the consensus that it is real work is well established). They’re being, therefore, unnecessarily lengthy by adding that breakdown in. They’re preaching to the choir while at the same time implying the rest of those present need education.
Also, by adding in the explanation, they get to talk longer and dominate the conversation.
Understand this is that person’s normal way of speaking. And if you call them on it, they attack by asking why you’re “uncomfortable” with their assertions, implying you must be, deep down, latently sexist or racist or whatever.
But, of course, it’s not their content, but their method which is uncomfortable. By taking such exquisite and lengthy pains to overtly show respect to those who aren’t even present, they wind up disrespecting those who are present.
It all boils down to context. If someone is more focused on the language used in a conversation (assuming the language is already respectful) than in the topic at hand, they’re not really into respect, but grandstanding.