It’s a charted procedure in the FMS! There are no landmarks you need to find other than the runway. It’s hard to miss that at night. It’s flown just like an instrument approach. It’s a very easy and benign charted visual compared to some other airports like LGA and DCA. The ILS is available for glideslope and FMS for lateral
SLF when it comes to airline ops but it sounds very much, in my humble opinion, to a management pilot who is unfamiliar with local procedures and using his management status to brow beat ATC. I say "unfamiliar with procedures" because if it was the airlines requirement ATC would have been familiar with it, LH has been operating there for considerable time, unless it was recently introduced, in which case it hadn't been adequately communicated. On the other hand perhaps the ATC was new to the position and not up to speed with LH unique requirement.
Unable to see LH's problem given the chart.