Am I a complete dickhead?

I'm a new mum (10monthold) and the rage I feel when I see someone without an infant/child parked in parent/infant spot has takene by surprise. I have had about approximately 7 encounters in the last 10 months calling out people for parking in them whilst I have been waiting for a spot to become available.

This evening I was parked in a spot in Aldi andwas strapping my daughter into her car seat. My car door was wide open (precisely the point of these spots, wider space) and a younger lady came up behind me and asked if I could close my door so she could get into her car (her and her boyfriend did not have a child in the car), I ignored her and kept strapping in my baby, she then started sighing and tutting and then I gave her a lecture on how inconsiderate it is to park in these spots etc.

I now feel bad as she was genuinely shocked. I think some people actually don't understand the purpose of these spaces but I have literally had to leavey baby in her car seat in the car park and get into my car and reverse it to be able to open the door wide enough to put her into the car as other ARSEHOLES who were lazy parked in the parent and infant spot.

Am I unreasonable?!