You mean they follow what many people consider best practices? https://softwareengineering.stackexchange.com/questions/1592... https://stackoverflow.com/questions/820466/never-delete-entr... https://serverfault.com/questions/31455/should-i-ever-delete... https://www.infoq.com/news/2009/09/Do-Not-Delete-Data http://udidahan.com/2009/09/01/dont-delete-just-dont/ https://stackoverflow.com/questions/2549839/are-soft-dele…
I imagine there are more pressing issues than the difficulty of implementing a schema.