That is absolutely false. A combination of Brood Lords and Infestors could consistently lock enemy units (including Ravens and High Templar) out of range to do anything substantial if the Zerg player was paying attention, and that combination with a few additional Corruptors could handle anything that Terran or Zerg could try to throw at it.
Once the first Fungal hit, there was no escape for the afflicted units, and Broodlings would further prevent any ground units from getting close enough to retaliate. That design gap is a major reason why HOTS reworked Seeker Missiles as a longer-ranged spell, and added the Tempest (the only Protoss unit which was not outranged by Brood Lord + Infestor compositions).
In WOL PvZ, the only way for Protoss to contest with a Brood Lord + Infestor composition was to attempt an Archon toilet gambit with the Mothership. If that failed to kill enough of the Zerg army then Protoss was guaranteed to lose.
In WOL TvZ, Terran could only contest Zerg by attempting to kill the Zerg player before they built up a Brood Lord + Infestor army. Anything else would be hard-countered by Fungal, Infested Terran, Neural Parasite, or Brood Lords once the composition was complete. Units such as Vikings and spells such as Seeker Missiles simply couldn’t reach unless the Zerg player wasn’t looking.
Even with the changes in HOTS, Brood Lord + Infestor was still a problematic composition, and it is still very dominant in LOTV despite the removal of Infested Terran and other changes that enabled Terran and Protoss to finally contest it.
No, it only came down to the Zerg player’s “skill”. A Terran or Protoss player’s skill did not matter because the combination of Infestors and Brood Lords could zone out and kill everything they could even attempt if the Zerg player was simply paying attention. The efficacy of an Archon toilet depended on Zerg’s ability to split their army in half, and the efficacy of gambits like Seeker Missiles depended on the Zerg player to fall asleep.
It’s telling that you main Zerg. No one who plays another race should ever want to go back to the balance nightmare that was WOL.
A slow moving, 125 energy projectile with only 6 range. Ravens could never get close enough to throw an HSM at a Brood Lord + Infestor army unless the Zerg player was asleep.