You may be overreacting -- there aren't enough details to say that you aren't. In particular, suggestions that your supervisor is acting unethically are very much not grounded, at least in what you've said. Slinging around such accusations carelessly will only hurt your reputation. (You probably shouldn't care much about that reputation if you really have left the field, but given that you worry about your name being attached to something not up to your standards, I guess you really do care about it.)
I would suggest analyzing this from your supervisor's side. He had a student in whom he probably invested a fair amount of resources, including grant money and time spent training that student. The student ended up producing good research, novel enough to be worthy of publication.
Now the supervisor is certainly aware that the student left the field, but he has an interest in getting the results published. He offers to do (or delegate) the remaining housekeeping in putting together a final manuscript, but wants to give credit where it's due. Unexpectedly, the student comes back with "I'm too busy, and I don't trust anyone else to publish my results."
Sure, you can prohibit a manuscript from being submitted with your name on it, and you can also prohibit having your name removed from something where you were undeniably an author-worthy contributor. But now that means the field is permanently deprived of your research. What was it all for, now that you refuse to let it be shared? Being uncooperative to the point where you censor your research can itself be unethical.
We did talk about trying to publish the results and I was, at the time, very positive to the idea, but I always understood that we were going to "get back to it" at some point.
Well, you never did, so your supervisor is stepping up and doing what needs to be done.
I don't want to work on this any more
His first draft of the abstract was either written to be misleading (over-emphasizing a connection to a much cooler subject), or he doesn't understand the context of the results, which makes me feel uncomfortable.
Dressing things up to get attention is not unusual in academia, nor is it unethical. At worst, if one goes too far, one gets a reputation for having too large an ego. If no lies are being told, then don't worry. If you want to micromanage every sentence of the manuscript, then you have to write it yourself and forbid anyone else from contributing.
I feel pressured to let them write a paper about the results and put my name on it ... I don't want my name on something I didn't actually write
I've seen a lot of papers published by more than one author. In a majority of cases, only one person ever did write all those sentences. (Where this isn't true, there tends to be a disruptive change of writing style.) The other authors contributed in other ways. If you were key to getting the results, your name should be on the paper, whether or not the manuscript was drafted by you personally.
I'm worried they will misrepresent things and do a bad job
In which case is the world a better place: (1) this research never sees the light of day, or (2) this research is written up in a more grandiose way than your modesty is comfortable with? Those are your only options, and unless this paper is going to be so misrepresentative as to be harmful (and how can you know that given that you've only seen an abstract?), you should probably go with (2). Be wary of making the comparison to (3) the paper is magically written the way you would like without any effort on your part. (2) might be worse than (3), but (3) isn't on the table.
There really is an easy negotiation here. Ask that whoever writes the manuscript be made first author. That way the research gets published, but everyone understands that the style and tone and other such soft features of the writing are probably not yours. If your name is on the paper you will be held accountable for its factual correctness, but no one is going to ambush the second author and say "I think you personally could have given a better account of how your paper connects with that cool subject."