I am willing to have this discussion with you and so have clearly experienced willingness
Nah, willingness is what leads to learning, so you can't say, "I was willing yesterday so now I have all the experience I need to make an accurate assessment". Even practicing Christians need a renewed willingness from day to day; a willingness to try new things and explore new perspectives.
moreover I have discovered truth eg 2 + 2 = 4 without any reference to Jesus or his teachings
This is an example of you not understanding the spiritual side. A student can understand 2+2=4 without understanding that it is called "mathematics". So too can someone tap into the Holy Spirit without understanding that it is the Holy Spirit. God isn't as concerned about names, titles, and categories as we are. He looks at the inside, so that a neighbor-loving atheist will be closer to God's spirit than a self-righteous Christian.
The parable of the sheep and goats is a good example. The final result was based on what they did and didn't do to love their neighbor, and the interesting thing about the sheep (who were rewarded) is that they seemed to not even understand that they had been helping God all along, which suggests this wasn't just an issue of bad Christians being punished while good Christians are rewarded, but rather that God looks at behavior rather than titles or categories.
But sincerity works both ways, too. Those people who show love can only do so because they tap in to God's spirit, but the spirit's job is to lead us into all truth, and eventually that will lead back to Jesus. At each step along the way our sincerity will be tested. The moment we stop moving forward because of some issue we don't want to deal with, we cease to be sincere.
God is so different from us. We use various categories like "Christian", "atheist", "Buddhist", "agnostic" etc to quickly summarize a set of beliefs and at times this is helpful. If I come across a Mormon, the title helps me to quickly understand where this person is coming from. I still need to be open to their personal sincerity, but at least I've got a starting point to work from.
But we often push these titles far beyond their practical usefulness into something more like "this is who I am; this title defines me as a person". We make the title a representation of who we are deep down, and so any challenge, change, or question of the title is like trespassing against truth itself. In practical terms it goes something like, an atheist cannot express love for their neighbor because neighbor loving is a Christian thing and you can't do Christian things unless you have the correct title. I have seen avowed Christians who will argue that an atheist volunteering in an orphanage isn't really neighbor loving, because they are not doing it "in the name of Jesus".
But to God that kind of thing is pettiness. He looks right past all the game playing, deep down into the heart and he judges each individual based on their sincere willingness (or unwillingness) to interact with his spirit a little more.
This is why your comments about not needing Jesus to understand that 2+2=4 misses the point. You're still playing the "My title is better than yours Vs I don't need your title" game.