after 3 months non supporting eu citizens should be deported, we dont do that.
No evidence that any EU country really does this. (It would be a nonsense anyway in the Schengen zone.)
Now imagine the court costs involved in doing this, the cost of immigration detention, the cost of transporting people back across the border, and consider how many years of benefits that would cover. Not to mention the cost of fighting the ECJ cases that would follow. I see no evidence that the UK can or should do this.
As for the tiny amount of NHS resources consumed by EU residents, I doubt you would ever get back more than you spent chasing the money. The UK system isn't set up like that (and actually, in some ways it is all the more efficient for it; a proportion of the 8% of my salary that I pay for my French medical insurance goes towards a bureaucracy devoted to chasing money round the system).
Finally, the idea that benefits in EU countries are always contributory is another remainer unicorn. Can't criticise leavers for chasing unicorns if we aren't prepared to acknowledge that the remain side has also been dishonest/willfully disinformed.