You won't lose points for your opinion on the ACT essay (no matter how ridiculous), but if you're set on doing this you have to be completely earnest about it. There's a risk in writing a satirical piece that you'll contradict yourself or end up with flaws in your logic because you're trying to be funny rather than providing legitimate support for your point. It's going to be nearly impossible to write something that is clearly satirical but at the same time advances a valid argument.
The essay is graded on four different criteria, which you can read more about in this article:
- Ideas and Analysis
- Development and Support
- Language Use
If you follow the guidelines for a high scoring essay, the satire element goes out the window and you'll just end up sounding insane. You might lose points in the development and support or organization domains. I'd advise you to abandon this plan and play it straight on the essay - it's not worth the extra effort to think of crazy supporting points for an argument that you don't actually agree with.