I think the overall tone of the comment does come across as rude, and the same point could certainly have been made with less "personal", more technical language that can't be read as including insults.

The phrase "you are not thinking" to drive home your point steps a bit across the line in my reading, creating an overall negative tone. Especially since "you are not thinking" can jump out at the reader, leaving its context behind and sounding ruder than (what I think) the intended reading was. (I think you mean "not thinking carefully about why you're doing this", rather than "you are braindead".)

Using the phrase "cargo culting" seems to me a clear way to point out the trap someone might be falling into. I didn't see that part as rude at all. I can kind of see where Oleg is coming from in assessing that part as rude, but I disagree. That phrase isn't the problem, to my reading at least, since I understand what the phrase implies in a programming context, and anyone on the internet can search to find out what it means.

(Although perhaps other people see the term "cargo culting" differently, with racist connotations, as another answer points out. Still, I think it's more the overall tone, and it would be fully possible to use that phrase in a non-rude comment to point out a trap someone might be falling into without making them sound dumb for not having recognized that fact.)

I think the overall tone of the comment does come across as rude, and the same point could certainly have been made with less "personal", more technical language that can't be read as including insults.

The phrase "you are not thinking" to drive home your point steps a bit across the line in my reading, creating an overall negative tone. Especially since "you are not thinking" can jump out at the reader, leaving its context behind and sounding ruder than (what I think) the intended reading was. (I think you mean "not thinking carefully about why you're doing this", rather than "you are braindead".)

Using the phrase "cargo culting" seems to me a clear way to point out the trap someone might be falling into. I didn't see that part as rude at all. I can kind of see where Oleg is coming from in assessing that part as rude, but I disagree. That phrase isn't the problem, to my reading at least, since I understand what the phrase implies in a programming context, and anyone on the internet can search to find out what it means.

(Although perhaps other people see the term "cargo culting" differently, with problematic racial connotations, as another answer points out. Still, I think it's more the overall tone, and it would be fully possible to use that phrase in a non-rude comment to point out a trap someone might be falling into without making them sound dumb for not having recognized that fact.)