TIPS ladders and ETFs are not the same thing. With individual TIPS bonds, at maturity, if the adjusted principal is less than the security's original principal, you are paid the original principal. TIPS bond funds have some of the same issues that nominal bond funds are having right now. They don't mature and you aren't guaranteed of ever getting your principal back.
Stocks lose money during market crashes, too, and there have been many more market crashes than deflationary periods so I guess I still don't really understand your point. Do you think TIPS are more risky overall than stocks? Most people have diversified portfolios as different asset classes do well in different economic times. I don't think anyone here is recommending 100% TIPS, but they do help save the day during high inflationary periods like we are in right now, which was the point in the Swedroe article.
If you are very concerned about prolonged deflation, then TIPS may not be a good choice for your portfolio. However, we have been more concerned about the possibility of inflation eroding the value of our investments in retirement ourselves - "Deflation rarely occurred in the second half of the 20th century. In fact, the dramatic and consistent price increases from 1950 to 2000 has been unparalleled since the founding of the country."
https://www.investopedia.com/ask/an...re-any-periods-major-deflation-us-history.asp