Well, the point was saying that our front three had outscored Liverpool's front three, which isn't true in the Premier League.
You could also argue that Liverpool played far more conservative this year. With no real replacements for their front three, I don't think they were really going all out in every game. I still think their front three are deadlier than ours; it is just that they hold back a lot more than they used to.
They are very capable of scoring a lot more than they do at the moment if they were more attacking-minded. When they were far less conservative in 2017/18, these were their goal-scoring stats (all competitions):
Salah - 44
Firmino - 27
Mane - 20
Last season in the PL:
Salah - 22 (Total: 27)
Mane - 22 (Total: 26)
Firmino - 12 (Total: 16)
We do have a good attack, but they do have things to work on e.g. Rashford's finishing in front of goal can still be dodgy.