Your argument is a twisting of the arguments those posters actually made.
#15 is reminiscing on the poster’s childhood. The poster makes no claim as to her current views on the subject of seatbelts.
#17 is another example of reminiscence. The poster again makes no claim as to her current views on the subject of seatbelts.
#18 is another example of reminiscence in the same vein as #15 and #17.
#49 is an injunction to drive carefully.
None of which is an example of the position you claimed they held. It seems that you have invented a position for them in lieu of responding to their actual positions or asking them, “What is your current position on automotive safety for children?”.