This claim is interesting, if true. Can you back it up? I spent 15 minutes on research, and my preliminary findings, using US statistics (I'm not American but it's just easier to google American stuff) suggest that:
a) about 42 Americans die to dog attacks per year (about 0.13 per 100k population) (very high confidence)
b) it looks like about half of those are kids under 17, with ages 1-4 over-represented (very high confidence)
c) most of those kids-dying-to-dogs deaths are not due to unrestrained dogs in public, but rather infants in their family homes, dying to dogs owned by the child's parents (low to medium confidence)
For example, WP gathers media/journal reports on dog fatalities, and has 16 records for 2023 (so presumably about 1/3 of the fatalities for that year). 6 of those are children. Of those 6 children, 4 died to the family pet, the other 2 died to neighbours' dogs while in their own home. Extrapolating from that that suggests that the number of American children killed by poorly restrained dogs, other than their own family, is roughly 6. Out of around 10k child fatalities per year in the US.
That doesn't seem "very high" to me, but that's just a matter of opinion. Do you have data that shows a different pattern?