If your new job is at a competitor, work to out compete them by using everything you know about their weaknesses and deficiencies to help your new employer take over their market share, suppliers, etc.
Share any applicable employment opportunities at your current employer or other non-competing companies to your current employer if they cannot bring them on with your former HON colleagues (make sure you are not on an active HON non-solicitation agreement).
Continue to dissuade anyone you network with or anyone that contacts you about taking a job with HON, and take the time to share your honest opinion about the horrible qualities of the company at every opportunity you have to highlight their true reputation.
Consciously choose to never buy or invest in any products or part of the company or other companies owned by HON, and encourage others you know to consider doing the same.
Ignore and never interact/network with anyone from management that you know/knew to be part of their Kool-Aid drinking horde unless you know them to be a standup person despite this, and if ever in the position to influence their future hiring at another company for another role, especially a management role, vehemently urge against it and do your best to get it denied.
Last but most importantly, going forward and from here on out, don't waste anymore of your mental energy or spare time thinking about them (except in execution of the above activities) as this is only another and one final way they steal from you.