What precisely? I don't see a counter-argument.
If you're saying not to use any CDNs then that's not very reasonable considering the service that CDNs provide.
If you're saying not to use any CDNs then that's not very reasonable considering the service that CDNs provide.
Everything on the internet is a product of thousands of vendors, hardware equipment and software components working together. There are millions of factors that can and may be compromised so the only realistic approach is risk management.
It's far better to rely on a well funded, staffed and capable vendor rather than building your own version. This is solid advice for everything outside of the expertise of your business so I'm not sure why a CDN is anything different. Assess the risk and do what works for you.