Your audience shapes your programming
Before continuing with this section, read the Allyship Journey page to see one way to segment men.
Deciding your target audience shapes your programming in two ways.
One, it shapes your outreach for events, newsletter signups, and membership signups. You'll naturally communicate differently, and you'll need more effective strategies if you're attempting to get participation from more reluctant people, (see the "Recruiting" page).
Two, it shapes the programs and curriculum itself – the articles you might choose to talk about in a small group discussion; the questions and topics you would plan for newsletter topics; the types of speakers you invite to be on panels or give talks; etc.
Theoretically, with enough time, resources, and volunteers, you could do programming that would engage all segments of people in different ways. In reality, you will end up prioritizing.
Biggest bang for your buck – train people who are already receptive. Just because someone is on board with diversity and inclusion (D&I) generally does not mean they would not benefit greatly from more self-reflection, systemic analysis, historical reading, examples of allyship behavior, and skill building practice. Plus, if you utilize the allyship training program, you'll also indirectly be interacting with the skeptical folks while your dedicated members practice.