Trinitarian doctrine is arrived at (in terms of systematic theology) from adding up details in scripture which, in themselves, do not explicitly state the doctrinal set. Complaining about a lack of an explicit statement of doctrine X when the case is made from adding up implications, is just like complaining (for example) that the scriptures never use the phrase “God the Son”.
If someone said “It’s striking that nowhere do the scriptures ever call Jesus ‘God the Son’! Point to where they do! You can’t do it! What, you admit they don’t? Ha ha! He admits they don’t! Have you ever wondered if you might be wrong? Why are you so dogmatic?” and kept repeating variations of this mantra whenever you tried to explain that it doesn’t matter that the scriptures never call Jesus ‘God the Son’, rejecting your explanations for why we believe that anyway while continuing to crow about you dodging the issues and how you can run but can’t hide–would you think they were interested in having a serious conversation? Or would you think they were desperately trying to find any way they could to avoid having to seriously consider your explanations for why Jesus should still be considered God the Son, the 2nd Person of the Trinity?
“And where does the Bible ever say there’s a Trinity?” they might hoot. "Nowhere! You can’t prove that it does! You know it and we know it! All your explanations for why there’s supposed to be this unbiblical notion of a Trinity are just unnecessary rhetoric, not worth our time to even acknowledge. You have no Biblical evidence for a Trinity at all! Show us where it says there’s a Trinity! What?–all we hear are crickets! Bring out your grand poo-bahs to show us where the Bible says God is a Trinity! "
That kind of insultingly dismissive and wilfully blockheaded attitude to trinitarians, is exactly the kind of attitude you’ve been having toward universalists ever since you got here, and it’s exactly what you’re engaging in every time people try to show (for numerous reasons) that it doesn’t matter if the scriptures never specifically show people repenting and being pulled out of the lake of fire, and you retort with “It’s striking that the scripture never show that, it would make so much difference if they did, but they don’t and so you can’t prove it’s true!” (or variations thereof.)
I’m not impressed when non-trinitarians do that (and thank you, by the way, to the non-trins on the board who don’t do that ). And I am equally not impressed when non-universalists try to pull the same move.