People use strategies of evasions in a zillion ways, most don’t involve any drugs (like making holidays to evade your everyday life), some involve legal drugs like alcohol (e.g. evade your social anxiety in social events). Using evasive strategies on it’s own is a normal part of live and in itself not a sufficient indicator for therapy. If the individual life suffers from it, then yes. What’s the point of doing therapy with someone who is fine, after all? All while people who actually suffer struggle to get any therapy to begin with?
We could also very well argue that all of these ways in which people use evasive strategies would be worth of therapy. I could get behind that (though there are good reasons against it, too), but see no reason to single out marijuana then.