Jesus said to remain in him. He said this because we have the option not to remain in him.
Commands are only given when violating them is a possibility. No one commands you to get older, tired, hungry, etc. because these cannot be helped.
There are many more Scriptures that support our capacity to fall out of God's good grace.
Now that it's come to my attention, I want to thank you for taking this approach and starting your own thread to espouse your understanding rather than just standing as a critic of someone else's. I think this is good.
And I think you do make a good point about the necessity to remain..... as well as the potential to fall away.
But I understand it differently-- one of these days I'll get around to saying why.... (in my own thread)