I would tel him to leave.
i would tell him he’s entitled to his views, but given his stance on testing and saying he just wouldn’t isolate I would tell him that I wouldn’t be party to putting other people at risk.
Incidentally, I am always 
at people who say it’s “just like the flu.” Those people have clearly never actually had flu, because if they had they wouldn’t be thinking that flu is no big deal either.
FWIW, I very nearly died of flu 4.5 years ago, and I was 43, not overweight, but unbeknownst to me I had a genetic heart condition which had previously never been diagnosed. This culminated in me developing two other, additional heart conditions.
In the past 4 years I have spent numerous nights in hospital, the worst of which being 2019 when I went in for scheduled surgery to replace a heart valve, which was cancelled because the surgeon didn’t believe i would survive. I crashed anyway, spent a total of 6 weeks in hospital, 12 nights of which were in ICU, 3 cardiac arrests, 1 stint on a ventilator, 4 weeks on oxygen even when I came out out of ICU, a different procedure called a mitraclip which incidentally wasn’t licenced for use on the NHS until December 2019, so a relatively new treatment as well.
That “new” treatment has transformed my life back to a semblance of normality, but I have been told that this is a short term fix and that I will ultimately need a heart transplant, although fortunate not to be on that list yet.
And now I have annual flu vaccinations, as does everyone else who is at risk of dying of the flu. And yes, some people die, because some people either don’t have the vaccination, or they have underlying conditions they didn’t know about.
If it wasn’t for the vaccine programme the death rate from flu would also be high.
And yes, there will always be COVID, and yes, people will always die from it. But that doesn’t mean we just ignore unprecedented amounts of deaths.
I’m not a shopping bleacher either, but I won’t entertain anyone who would put me, or anyone else at risk. As you say, there is middle ground, but the difference between the two extremes is that the shopping bleachers aren’t actually putting anyone at risk although if they are e.g. transferring this fear to their children then it does need addressing.
But the deniers are actively contributing to the deaths of other people, those with underlying health conditions which they didn’t know they had. Or who because of those conditions cannot be vaccinated.
We don’t have smallpox any more because of vaccination, vaccination which incidentally was mandatory iirc.
We don’t have the amounts of deaths from measles or numbers of children born prematurely with severe SN because of rubella because of vaccines
We don’t have the numbers of cases of TB because of vaccines
I’ve unfriended about 25 people on facebook because of these kinds of views. Some of who have have been longstanding friends. I wouldn’t choose to be make friends with a COVID denier, as such I don’t choose to continue friendships with such avid COVID deniers either.