i bet to differ. a difficulty drop will entice more miners to switch on redundant rigs, putting more BTC into the market, thus, having effect on price.
A difficulty drop means miners were already shut off to begin with. The only way more bitcoin come into the market than expected is if the hashrate increases again (as the difficulty re-target will lag behind)
(you are assuming the difficulty adjustment overshoots but it may be accurate enough that no new miners enter)
BTC price is largely commanded by market demand, and with lower difficulty, market demand to purchase BTC goes down - as does price.
I would not subscribe to that generalization.
When
mining profitability goes up a lot demand to purchase BTC should go down. Difficulty can drop and yet still mining may remain unprofitable enough for demand to be mostly unaffected.
[edit] just to be clear, that is one factor in a complex system. When mining profitability goes up it will most likely be to external factors that also strongly influence demand