The speculation I have heard is that the terms "deploy" and "link" are both ill-defined and have not gotten proper testing in the courts. So there is no case-law saying that pushing your changed binaries to 1,000 internal sites (or even better: partially owned subsidiaries) does not invoke the clause. Or what does "linking" mean in the context of a database driver? What happens if a well-meaning employee loans out a modified binary to a customer to see if it fixes their problem? All of that makes lawyers nervous, and what makes one lawyer nervous has the potential of making other lawyers rich at their companies expense.
Just because you read something and come to a conclusion does not mean that people who come to other conclusions are "uneducated".
I run a tiny business. AGPL is banned there too.
It isn't an "unreasonable fear". It is a reasonable decision based on mitigation of risk. AGPL is a risky license for end users; it goes too far beyond the Four Freedoms.