They actually wouldn't, like go actually to their reddit page or his insta and you will see that they are obsessed with him, Liverpools defence has been insane, clean sheet almost every match, and Lovren is a big reason for that. The Spurs game is the only reason nobody calls him World-Class, but he has been that since then.
Depends which Liverpool fan you refer to doesn't it? An average guy who knows no better about football and thinks VVD is the best in the world, and whose memory doesn't go as far back as before 2018. They might tell you Lovren is world-class. No surprise there. In the same way you would see thousands flocking to support Griezmann after these statements from him or his camp that he is on the same planefield as Messi and Ronaldo. Same mindless crowd.
The Spurs game is not the "only" reason. His track record since coming to Liverpool is. He came as the revered Southampton transfer along with Lallana to replace Daniel Agger and flopped so hard they had to go back to the market multiple times to cover up the hole to have any hopes of keeping Coutinho long term. They didn't.
Almost every match? What?
4 clean sheets out of 8 in December 2017
1 out of 6 in January 2018
2 out of 4 in February
3 out of 5 in March
4 out of 7 in April
1 out of 4 in May
2 out of 4 in August
2 out of 6 in September
19 clean sheets in 44 matches. Not even every other match.
Basically they had a good spring and with VVD introduction you could even bother starting to count them. He stopped them being top heavy and it's a good record. Not "insane" at all.