Yes, that's the usual 'argument' except that this does not even seem to be true (return flight from London to New York seems to emit about 1t per passenger when a typical Brit otherwise contributes 7+t, so that's 1/14th of personal annual emissions per flight).
In any case, not everyone flies over the Atlantic every year, so that overall and in the grand scheme of things aviation should not be held as a priority.
Focusing on aviation is a distraction.
While I do think it's mentioned more than it should be, it can't be denied that it's a major factor.
It is not as hard as: just stop driving with your car to work! Hmmkay?!
The issue is that it focuses on something that is not a priority and it is so largely on ideologically grounds.
Your second sentence is actually highlighting a real aspect of the issue: Many people prefer to do something easy rather than something effective.
We have been systematically strip mining the planet for decades. We need to take a step back and calm down.
If you're banging through your credit card, you knock it all out. You start from the bottom up, not the top down. You look at what you absolutely need and slowly add things back in.
We've hit the credit limit on our ecosystem.
But the reality is that there many, many things to do that are more effective before even starting to look at aviation.
I don't understand the point of calling for "civil disobedience" (which is usually an euphemism for blocking roads and airports, and alienating public opinion in the process). What does it achieve? If you want to use your individual power do it constructively by changing your everyday routine and behaviour.