The parable of the sheep and goats, if understood in context, is clear. The goats never knew Him nor He them. They did not believe.
John 6 has been hashed out many times before so I won't go into that again. But to use your objection of one passage that is precisely what Roman Catholicism has done with John 6....and rather badly I might add as they go from symbolic to literal in the same passage....they've got it backwards.
To take your position you have to admit Jesus did not tell Martha the whole story. In other words, He lied to her.
I do not believe that is the case. He did not lie to her. He does not lie to us.
You have a funny way of thinking if you think Christ lied to Martha by not giving her the entire theology of soteriology in this one passage. He told her what she needed to know at the time....and he told other people what they needed to know at those times, and these collected teachings are combined into the New Testament.
You seem to want to screen out everything and just focus on this passage regarding salvation....and what gives you the right to do that?
The goats, by the way, were not condemned for not knowing Christ...they were condemned for not *doing* something for Christ. The passage is very explicit. And again John 6...whatever it means if you don't want to go down that rabbit hole...it clearly states that you must DO something to merit eternal life.
It's hard not to read you and see the lingering effects of Luther--he had a big problem with scrupulosity and forgiveness, and he thought he could game the system by just declaring himself righteous by fiat and then sinning boldly all he wanted. Biggest scam the devil ever pulled on the Christian faithful. Don't get sucked into his trap.