First let me stress that I certainly agree that there is a problem with 'lazy' titles. A strategy I noticed is to to add adhoc numbering.
That said, you wrote:
as you can see in the edit history, it originally said "Isomorophism between modules"
However, in actual fact originally it said "isomorophic of module" where the motivation does not apply anymore. Further, in the body it then says "are isomorphi".
Thus, I'd assume honest typing and language issues or less charitably general carelessness, yet not some more subtle motive.
The title you mentioned came about in the second revision, by somebody else. For them I'd assume they had overlooked this particular problem when they thought they were 'transforming' "isomorphic" to "Isomorphism" and thus the extra "o" in error stayed there.
For the warning. Frankly, I am not sure that a 'better' warning would help all that much. Given that such things are not changeable easily, I would not consider it as a priority. In any case, we also say at other places that and why users should use telling titles, for instance on this advice page every new user must confirm to keep in mind.
I agree, of course, that it is important to fix such titles. Such an edit could be accompanied by an explanatory comment, maybe something like:
I changed your title. Please be especially careful when choosing a title. There are many new posts every day and the title is all that some users that could potentially answer your question will ever read of your post. Moreover, try to make sure to get the spelling correct as this is important for users finding your post via searches. If there already is a question with the same title, try to add more details to the title rather then to modify it in a superficial way.
To stress how it is in their own best interest to be specific maybe could have more impact.
In fact, as Arnaud D. recalls, there is also template along these lines. See List of comment templates