Why? It has its benefits too. For example it can reduce viral load in the mouth, reducing the risk of COVID transmission for example. I think people can make their choice as to what product they want to use and what tradeoffs they are okay with.
In regards to benefits, peroxide based mouthwashes do have similar lysing effect but less drying effect - and this has been known for ~ a decade; and fluoride mouthwashes should actually activate the salivary glands, in addition to lysing. But, one could speculate that peroxide based mouthwashes would have a similar result to alcohol based in this study based on what we know about wound care (that peroxides kill both the bad and good bacteria)
Alcohol is suspected to be carcinogenic.
https://drugfree.org/drug-and-alcohol-news/australian-study-...
https://www.medicalnewstoday.com/articles/alcohol-based-mout...
Everything is given high enough doses.