I have an unpowered one with cold water and I agree that it's not an issue at all. It's even refreshing!

Also, the argument isn't necessarily about preventing something bad from happening, it's also about just feeling clean. People who have not tried a bidet cannot really say whether they would feel better/cleaner with TP or a bidet. It's like if you tried to explain to someone who has only ever used wet wipes to bathe that a shower makes you feel better. Sure, wet wipes may objectively clean you but those who have used a shower can speak to the subjective benefits of feeling nicer.

The counterargument that "TP works well enough" is not a very strong one to my mind, if there's something that works better with no real downside.

1) "especially with no way to aim things before hand" - The precision and accuracy of the water stream is extremely high. On less sophisticated models, which can be had at local hardware stores and Amazon in the US for less than $50, you "aim" by adjusting your seated position. In other words, you bring your @* to the water stream. This sounds like more of a chore than it really is. It's a game of inches, not feet. More expensive models have some range parameters that can be changed for front and rear washing preferences.

2) "leads me to expect a mess being sprayed around the bowl" Practically speaking this has not been an issue for me.

3) "outside the bowl if you don't have a good seal" ??? You are seated on the toilet seat. Unless you weigh considerably less than me, I'm not sure how you wouldn't have a seal.

4) "Aerosolizing feces is already a problem with the flush, now we are splashing it around?" This is an interesting point, and one that I had not really considered. I am not aware of any studies in the literature (and I suspect it would be a bit of a red flag about myself if I were) that looked specifically at aerosolization during the actual act of using the bidet. However, a cursory search did yield a few studies that looked at bacterial colonization of the nozzle. This can be concerningly high in a shared use toilet, though the limited amount of studies are not in good agreement here. Iyo et al. (2016) found Pseudomonas aeruginosa on 2% of bidet toilets in a restroom on a university campus; a different study noted that in a university hospital, 34% (n = 10) of bidet nozzles contained isolated of Staphylococcus aureus (Katsuse et al. 2017). Tsunoda et al. (2019) found that there was an 87% colonization rate of bacteria (all species) in hospital toilets with bidets.

My follow up question would perhaps be "so what?" when you consider the issue in the frame of a personal toilet (rather than a toilet in a hospital), which might be shared with your family members and, more rarely, friends. I personally consider it a negligible risk in the grand scheme of microbial activity to which I am exposed elsewhere. I do take the nozzle cleanliness seriously, and I make it a point to clean the nozzle with a bleach-based toilet bowl cleaner.

That said, I agree with you that this is a relative unknown and one about which I would like to know more.

5) "And I assume you still need to use TP to wipe up, but anyone who has used toilet paper around water knows how ineffective it is at drying things." You do need to do this. Anything more than single-ply is up to the task. I have never had an issue with ineffective drying. Sometimes I only need to use 1-2 squares.

6) "Find a way to tell people how they actually work" They shoot a stream of water up your butt. This is conceptually simple enough (and logical, to boot: I'm sure everyone here is well aware of the common argument for bidets that water cleans better than paper). I personally think the bigger issue is that people are uncomfortable with the idea of something going up their butt, not that they don't understand the answers to the questions you've posed.

7) "Put them in hotels" I have seen them at a hotel in Hawaii, but this was due to Japanese influence. I do not think that most hotels would take on the investment in order to be the harbinger of change in this country. It might cut down on their TP costs, but they buy (horrible quality) rolls for pennies on the dollar.

Bonus: I recommend watching the South Park episode wherein Randy buys a bidet, for further (albeit fictional) testimonial to their greatness.

--- References: Iyo, T., Asakura, K., Nakano, M., Yamada, M. and Omae, K. (2016) Bidet toilet seats with warm-water tanks: residual chlorine, microbial community, and structural analyses. J Water Health 14, 68–80.

Katsuse, A.K., Takahashi, H., Yoshizawa, S., Tateda, K., Nakanishi, Y., Kaneko, A. and Kobayashi, I. (2017) Public health and healthcare-associated risk of electric, warmwater bidet toilets. J Hosp Infect 97, 296–300.

Tsunoda, A., Otsuka, Y., Toguchi, A., Watanabe, K., Nishino, R. and Takahashi, T. (2019) Survey on bacteria contamination of bidet toilets and relation to the interval of scrubbing these units. J Water Health 17, 863–869.

Abney, S. E., Bright, K. R., McKinney, J., Ijaz, M. K., & Gerba, C. P. (2021). Toilet hygiene—review and research needs. Journal of Applied Microbiology, 131(6), 2705-2714.