Can you explain why this is a ' troll ' guide?

Well, for Tryndamere it is a nerfed keystone, as it gives ad, not on-hit damage when Tryndamer relies on auto attack. Now it gives him less dps and takes longer to get full stacks. Now it is only good for champions who have high attack speed plus a lot of abilities that scale with ad. His only ability that scales with ad is his e, and doesn't have a short cool down.
TL:DR Warlords still better, if not much better

I prefer to use Warlord's Bloodlust because most of the top matchups require more sustain. Fervor is only good for early game when you want to play aggressive, which is often very risky.

It is a good question because black cleaver is a strong item right now. However, all the stats it gives aren't that important for Tryndamere to reach his power spike. There is a cdr build that involves black cleaver and cdr boots. For some people that build works , and it can be very good in some situations. In my opinion, going for pure crit , attack speed and damage items is better. You can't afford to take black cleaver early, because it will delay your power spike too much. Picking it up later in the game can be a good choice if enemy team doesn't have too much cc or same kind of damage. I would still rate it as a mediocre item for Tryndamere.

I would recommend you to just keep practicing with same build, because statikk shiv won't help you much with last hitting. It will just push your wave fast and you can clear caster minions with E if you crit I guess. You could go try it, but I think phantom dancer is a better choice now, even if you lose some cs.

I think it's good for Tryndamere if you correctly utilize youmuu's active ability. Building it as 2nd or 3rd item, seems like it could work against some champions that you really have to all in. Getting Phantom dancer, Youmuu's and life steal item, looks pretty strong for split pushing.

Those are just 3 examples of full builds. You should build according to matchups, team compositions and situations. Always start of with core build: attack speed boots, botrk and phantom dancer. You are already very strong then. What you build after that depends on those 3 things I said. For example, if enemy team has a lot of squishy champions, go for IE right away. If they have 2 or more tank champions who stack armor, go for Last Whisper. If they have a lot of magic damage or cc, go for Mercurial scimitar. You get magic resist and qss, and also more lifesteal for sustain against ranged magic damage. Then you have 4 items and want to move on to making the decision for 5th item. It is usually the best to have one tanky item by the time your build reaches 5 items. Try to estimate whether you need more items with the right stats against those enemies. If you need more magic resist go for hexdrinker (maw of malmortius). If they have mostly physical damage consider going for Deadman's plate. If they have a lot of burst damage and assassins with mixed damage, go for Guardian angel, it's very strong now because it's cost has been reduced this season. Same process goes for last item. I hope this helps and gives you a good insight of how it should work. Between bronze and plat you should usually go for more damage items because Tryndamere is pretty tanky on his own, and enemies aren't good enough to know how to kite you properly. The higher the elo goes, Tryndamere should build more defensively, even in early to mid game, when enemy has something that they know how to counter you with and you simply can't afford to go full damage.

You are right about Tryndamere's powerspike. Playing with ignite and trying to all in your enemy in early levels (2,3,4) is a good idea. I would still never use any crit runes. Attack speed is just much stronger stat. I tested it many times, even just in custom to see what does more damage, and attack speed does more burst and more sustain damage at every point of the game.