If there's a severe drought in Laos and the country can't import electricity at affordable prices, then reducing the electricity supply to crypto miners is justified. I don't believe that the authorities in Laos are using the drought as an excuse to shut down the electricity supply to the crypto miners. If the situation continues I don't think that there will be problem for the crypto miners to just move to another country.
I don't have any data about the capacity of crypto mining facilities in Laos, but I can assume that the mining power is insignificant.
Laos belong to Mekong delta nations with China and in China mainland, we know they usually have big changes in rain, flood seasons. I agree with your opinion on likely impacts of drought on power supply especially hydroelectric supply in those nations. Laos is at nearly the end of Mekong delta so it has more impacts from drought than China.
Bitcoin and cryptocurrency mining is not what governments care most for their national economy and related industries that need electricity supply. When their nations' electricity supply has problems, they have reasons to temporarily cut supply to Bitcoin and cryptocurrency mining farms.
Bitcoin mining difficulty posts biggest drop since ASIC eraThe difficulty drop is a result of the decline of the average total computing power racing on the network in the last two weeks as many Chinese miner operators have unplugged their machines to migrate to fossil fuel power stations from hydropower plants.