Failing to follow the rules is not limited to HOAs.  Lots of nonprofits fail to follow the rules.  For some, it is because they don’t know what the rules are.  For others, it is because they don’t care what the rules are.  As a member, you have a lot of options.

You can seek an audience with the board to talk with them about it.  Do they recognize what they are doing is wrong and are they willing to correct things?  A group of you could call a special meeting of the other members to discuss the situation and expose the incumbents for what they are doing wrong.  Is the improper conduct serious enough that others will care and put pressure on the board for reform?

You could call a special meeting to throw out the incumbents (or at least those you think are leading the failure to follow the rules) and replace them with representatives of the group that care.  You could wait until the next scheduled election and campaign for your candidates to be nominated and elected.  If you want to spend a lot of money and a lot of time, you could file suit to force them to follow the rules, and/or to invalidate the actions taken by an improperly elected group.  With the time it takes to bring a case to court and then go through appeals, even if you expect to win, litigation may not be a rational choice, but it can raise havoc with the functioning of the Association.

Ultimately, however, it all boils down to whether you have the votes from the members to cause a change. It may take a serious campaign by you and the others who have sent the disregarded email to generate the support among the members for a change in direction.  A nonprofit membership organization is much like a governmental unit.  It tends to get the governance it deserves and demands.