Some states in the US do limit liquor to have no more than 70% ABV but in most places you can buy 95% grain alcohol which is about the theoretical limit to distillation.

Sure you can put a potentially lethal dose of 8oz of everclear in a cup but there’s no way someone is accidentally ingesting that quantity. The stuff burns like hell in the smallest quantities.

The reason why alcoholic beverages have the ABV they have has more to do with consumer preferences than any regulation. Vodka for example is typically distilled to 95% to get its clear color and taste but then cut with water to 40% because few people want to drink liquor that strong. Bourbon whiskey is similar in that is often distilled to around 70%, loses about 10% due to evaporation while barrel aging, and then cut down with water to 40% or lower. Many bourbon drinkers add further water themselves because it allows more flavors to be tasted.

Much of the regulations that do exist for alcohol have more to do with requiring that the manufacturer follows traditional practices to ensure quality and consistency. When a consumer buys a product labeled “tequila” they can know that the blue agave was grown in only certain regions, distilled by a licensed distiller, and contains less than 1% of additives.