Design is a decision making tool. Using design processes instead of declaring your position by defining words can be really uncomfortable. I like Scott Berkun's tweet on this where he explains how people often derail design and policy processes and instead have a very long conversation on definitions.
There is *always* a way to derail any conversation into a debate about definitions. ALWAYS. Some people prefer this. It brings the discussion back to familiar turf. And the conversation becomes an endless series of "when u say x do you mean y? But is z part of y?..."
Source: @berkun