Two carefully built rankings of the same group of strikers routinely produce different orders. The disagreement is not carelessness; it comes from the fact that no single question is being asked.
Goals measure output, not contribution
A goal total records what a player finished, and says nothing about how the chance arrived or how much of the work he did to create it.
A forward in a dominant side receives more and better chances, so an identical finishing ability produces a much larger number beside his name.
Rankings built on totals therefore rank teams as much as players, which is defensible if output is what you want but misleading if ability is.
Efficiency measures rest on small samples
Conversion rates and per-shot measures attempt to isolate finishing, but a season contains few enough shots that fortune moves the figures substantially.
A striker who converts unusually well over one campaign frequently returns to an ordinary rate in the next, without anything about him having changed.
Ranking on efficiency consequently produces unstable orders that reshuffle each year, which is why it is rarely used alone.
Role changes what should be counted
A forward asked to press, hold the ball and bring runners into play is doing a job that produces fewer goals by design.
Judging him against a poacher whose only responsibility is to occupy the six-yard area compares two different occupations under one heading.
Any ranking has to choose whether it is measuring goalscoring or centre-forward play, and most quietly mix the two.
League strength is an unsolved adjustment
Comparing across competitions requires an assumption about how much harder one league is than another, and every method for producing that number is contested.
Small differences in the assumption reorder the entire list, particularly for forwards scoring heavily in less-scrutinised divisions.
Because the adjustment is invisible to a reader, two lists can appear to disagree about players when they actually disagree about leagues.
What a useful ranking states up front
The rankings worth reading declare what they are measuring, over what period, and what they deliberately exclude.
A list that says it ranks non-penalty goalscoring in one league over three seasons is making a claim that can be checked.
A list that promises the best strikers without qualification is combining incompatible measures, which is exactly why it cannot be reconciled with the next one.