"it won't improve the productivity of level 1 programmers"
Gotta tell you up front, there's not much hope with people who say things that ridiculous. This is tantamount to saying "Visual Studio isn't worth the cost for junior developers, they can use Notepad.
In my experience, anyone who asks for Resharper (or any other productivity tool) is probably going to make good use of it because they know already what it's going to give them.
The people it won't help is people who don't know what it offers and aren't surrounded by people who help each other. I've been using it for years now and I still keep finding new features that save me time. Even if you're not the kind of person to get all the benefits, in a decent sized project, Find Type and Ctrl-Click alone pay for the license.
I guess you could try that argument. Or you could try the long-term approach - the longer someone is given resharper for, the more benefit they get from it, so why wait until you're a senior and waste that learning curve then. Or you could try the argument that being a lowly level 1 developer you're going to need help from seniors and they're going to be less inclined to come to your machine if it is less functional.
But honestly, I don't see any argument that's going to get past someone who says things like that. I'm thinking the only thing going through their mind is: if I don't invest in making my seniors happy, they leave (or worse, go over my head to my boss); if I don't invest in my juniors, they don't. I doubt the productivity argument has ever washed.
I feel for you. Best advice I really have is that this is your first lesson in questions to ask at interviews when you do move on. My guess is you'll be learning a lot of things about how to spot companies you don't want to work for.
Incidentally, that was part of the argument I made when asking for licenses for my team (which wasn't a tough fight - one email): if resharper does nothing else, it attracts good developers to your company.