[1] https://www.freebsdfoundation.org/donors/
[2] https://people.freebsd.org/~rrs/asiabsd_tls_improved.pdf
[1] https://www.freebsdfoundation.org/donors/
[2] https://people.freebsd.org/~rrs/asiabsd_tls_improved.pdf
That's the free rider problem, one that the GPL (and the AGPL) was designed to avoid.
It's true that many of those companies which use FreeBSD wouldn't touch a GPL codebase (and all the more so an AGPL codebase), but that't the point - while some chose FreeBSD because it's fast/stable (NF and WhatsApp), others chose it because they don't have to contribute back.
All of this free, open, etc. software works in part because of a "pay it forward" approach to the community. If people shame big users for not "paying back" enough, rather than finding more productive means of encouragement, the whole system of free tools becomes less tenable because future users will pick other tools that don't have PR risk attached.