I hear ya
Yeah It is meant to be humorous, and I get it. Consider the members who put in the time, don't gripe about it, follow the rules, and feel as if they are not getting what they want from the organization. Reading that letter might only make them feel more isolated from the club they joined.
Most clubs have a hard-core group of about 25% of membership that shows up for races, social events, work parties, etc. They also serve leadership roles.
The others may not have the time but are avid enough to join, and may have some legitimate concerns too. Ratings shenanigans are probably most common, followed by feelings of neglect.
I'm just sayin your letter might turn some people (potential members?) off.