I have a team lead who seems to think that business logic is very subjective, to the point that if my stored procedure has a "WHERE ID = @ID" -- he would call this business logic
What approach should I take to define business logic in a very objective way without offending my team lead?
I really think you just need to agree on a clear definition of what you mean when you say "business logic". If you need to be "politically sensitive", you could even craft the definition around your team lead's understanding, then come up with another term ("domain rules"?) that defines what you want to talk about.
Words and terms are relatively subjective -- of course, once you leave that company you will need to 're-learn' industry standards, so it's always better to stick with them if you can, but the main goal is to communicate clearly and get work done.
One way to differentiate is that "business logic" is something the customer would care about and that could be explained to a customer without referring to computer-specific words.
You could try to argue your point with a timed example, run a sql select against an indexed table and then run a loop to find exactly the same item in the same set but this time in code. The code will be much slower.
Let the database do what it was designed to do, select sets and subsets of data :) I think realistically though, all you can do is get your team together to build a set of standards which you will all code to, democracy rules!