Yes.. again these are poor examples, you could show any example of any fleet killing another in a quick way, DE still dont have a the top 3 highest win rates atm iirc, all those examples are showing a good player, picking a specific build against weaker players that are very vulnerable to that build.
First examples are against Tau.. well eldar in general are strong vs tau, unless the tau player has any brains. Neither of those Tau players used enough escorts, and neither used them properly, to scout ahead. The escorts should be well ahead of the main ships to spot the enemy so your big ships can.. you know.. actually use their super long range weapons. Instead he stays all clustered up, no decent scouting whatsoever, against a stealth faction that is most likely going to have torpedoes.
The DE player, is popping the wraithbone ability to give himself 75 frontal armor for 15 seconds thats why hes ramming and doing so much damage while not taking much himself. But it only lasts 15 seconds and only affects the front armor.
I dont see either of his opponents scouting, using bombs to force evasive boosts. Spreading out. That armor ability only works within 9k of the flagship, so spread out and then its not nearly as effective. They also dont anticipate the ram and dont present their front to his ships letting him ram them in the sides or rear, also doesnt use brace when he can see the rams coming.
It basically like playing against a guy with a shotgun, and your playing a sniper. You have the ability to scout him, and do lots of damage before he gets to you to even it up but instead your just letting him get close for free.
That being said i DO think DE need nerfs, but in the points department, Problem i have win DE atm is that all their battleships are so cheap. They all have the exact same firepower, the obsidian rose only has 3 extra lances, which arent even that good now that the lock on got changed.
Their Battleships should all be minimum 400 each imo, they also have good troop efficiency had 70% assault crit chance which makes their low price even more ridiculous