I was being sloppy, but am referring to the following sentence in the article.
Approximately 30% of unicorn investors had significant protection against a down round IPO.
So you're right. If the company goes bankrupt, unicorn investors are going to be first in line to get their money back. This matters, and does help get funding at higher valuation.
But it is not nearly as inflationary as terms that say that the investor still gets paid on a successful exit that is merely not as good as hoped. And the latter is the kind of term that could cause the valuation placed in the company to be totally disconnected from the value that the investor thinks the company should be worth.
That means that for the most part, the investors are betting that the company is actually worth at least what they are investing in it at.