The stance isn't exactly coming out of left field. Like Quentin Tarantino, Nolan is a staunch defender of film and the classic movie theater experience. He wants movies like Dunkirk to "make you feel like you are there," and to him that means a theatrical release. You aren't going to get that watching on your TV, he contends. That's debatable (it's not hard to get a large TV, and Nolan will watch Blu-ray movies at home), but it's easy to understand the logic. And it's important to stress that this isn't a bitter grudge against Netflix. To Nolan, it's just a question of the internet company making a "more admirable" investment in movie projects than it does now.
The problem, of course, is that Netflix is unlikely to be swayed by Nolan's arguments, no matter how nuanced they are... at least, not so long as the company is attracting millions of new subscribers. It primarily sees theatrical releases as adding prestige to its streaming business, particularly when it makes them eligible for awards. Where Nolan is interested in maximizing the dramatic impact of his work by using an 'ideal' format, Netflix is largely interested in making its projects accessible to as many people as possible. Those are frequently contradictory goals, and you're unlikely to see the two parties shake hands unless one of them has a change of heart.