That’s hard to answer. It would depend on the greater good that the forced blood donation would be for. If it is because joe billionaire needs it for some elective surgery, no. If it is for some sort of pandemic and my blood will help sure. Especially if it is like a system that incenivises the donation in some way. “Hey patient A needs blood if you donate you’ll be higher up on the list for xyz” or something
The logical followup is where is that line to decide if it’s “enough of a greater good” and who gets to decide? My answer to that would be people that are smarter than me and people we put in office to help make laws. Regardless of what they decide i will have an opinion about it and look to discuss it.
I also give blood quarterly anyway. Getting out of forced blood draw would be easy, recent tattoos, rusty knife of unknown origin cut your skin while you were walking, or participated in an orgy with people of questionable virtue will all get you politely asked to leave. They don’t mess around with potential blood contaminants.