Sounds like an unreasonable seller and the most likely reason for them not wanting an offer with a financing contingency is the property is in too rough shape to get financing on it (structural damage, fire damage, etc.) or won’t appraise anywhere near asking price.   

Often times when a builder/buyer moves too fast, or is too busy and overlooks a key piece of due diligence, the unethical ones will try the "scorched earth" method and blame everyone but themselves, even when they know it was their own mistake, and they'll see if they can scare you, the seller, the title company et al into paying damages/fixing their problem. 

What steps would you recommend to minimize damages and resolve this issue efficiently?

Especially if seller just received a windfall from the sale it is definitely worth suing for damages.

If your occupancy rate drops, you may able to patch the damage by trying other platforms but this will further decrease your ranking on the system in the future. 

What is the point of damaging all of your relationships and being unhappy to be wealthy for the last 20 years of your life?

They're still trying to scam people wouldn't that help to keep the damage to a minimum?

Not worth the liability risk and the potential damage pools leave.

Tenant further acknowledges and agrees that they shall be liable for all damages to _______ system due to intentional or negligent acts by the tenant, it's invitees, guest,  agents or licensees" 

Quote from @Michell Chase: It isn't a large amount but my concern is that if I remove the tenant in July I have no deposit in the event that there are damages to the unit.