I won't say golem pilots are bad pilots; Its more of if you want to make the golem work in incursion context;
1) you need to know what to shoot/ where to anchor (shoot reverse order to maximise dps)
2) you need to change your golem fit to maximized its effectiveness (not allowed for line pilots)
3) you need to know take risk in tcrcs (aka bastion the entire site)
4) you are also limited to battleship targets in terms of effective application (nowadays the frigate/cruisers are the bottlenecks in terms of site times)
If you happen to fly with @Venus Aeternum in a golem previously he does them perfectly; pulling aggro even over that badged kronos pilots in the entire site
Henceforth if you don't maximise all the above points; you are basically a vindicator w/o webs (2.4k dps) instead of a paladin (3.2k) or kronos (4k) you could potentially be flying
5) Main purpose of Kronos is basically just DPS. Golem can TP while doing slightly lesser dps but do remember missile main weakness is the travel time. Sure the target painter can help blooming the sig but in current fleet status there are only 1 or 2 golems in fleet at any time. 2 TP wont help to vastly improve site times if i were to compare to webs in terms of utility. Missile trade application time for max damage application. Thats why by the time your first missile hit the the rats; its died and you wasted next 3 cycles of missile damage whereby the other marauders does instant application (thats why you shoot reverse order but you dont get the benefit of the fleet focus fire)
That's why the a golem can bastion all the way in a tcrc if it jumps immediately once the ountuni is down; allowing the rest of the marauders to safely bastion until end of site.
Given the missile travel time compared to instant application of other marauders; golems are further degraded in terms of contests given how fast rats die. That is why golem is not an end game marauder hull for incursion in this one focus situation.
The initial implementation of the golem into WTM was to serve as a bridge for people who was already golem trained but doesn't want to fly the starters ships and allow them to transition to the other marauders much quickly namely Kronos, Paladin and Vargur. Hence that is why its was initially placed in DPS (Optimal) instead of Mar DPS. It was not meant to be an end-goal marauder class otherwise we would have lumped it in Mar DPS or Mar Sniper.
The following link above was in the wtm in game channel MOTD from December until we did a recent change to streamline the wtm ships. However the new incoming patch might cause the golem to become more relevant but WTM CC will need to test them before deciding any changes to the golem.
I hope you understand what i'm trying to bring across the reason why golem are bad for incursion and not saying golem are for bad pilots. Rather it requires a lot effort and knowledge in order to maximise their effectiveness; otherwise its just a bad platform to use for the end game incursions especially in 1 focus situation where we contest other communities basically every day