Reading is a vital life skill. Even with computers and modern technology, not being able to read fluently is a major hurdle. IMO supporting reading at home should be considered as normal a part of parenting as making sure your child is fed and clothed. No child is going to embrace reading as an enjoyable activity if the message fed at home is that reading is a 'chore' and has to be timetabled in.
However, it's not really that black-and-white is it.
Some parents cannot read themselves, or read in the language the book is written in, or they read so badly that they are worried they might 'sabotage' their child's burgeoning ability to read and so prefer not to interfere.
Some parents may not have time. I know it only takes 5 minutes, but there are a lot of 5-minute tasks to be slotted in just for school, let alone other aspects of life. Sometimes things have to be prioritised, with the result that some tasks are dropped.
Sometimes a parent has to rely on family members/childcare to put a child to bed etc before they get home from work, so unless the child is kept up late, there is no opportunity for them to read to the parent, and the babysitter may not be willing or able to fulfil this function.
Then you get parents like me. I don't always fill it in my child's reading diary because I have read daily to my DC since they were 4 months old and books/reading is a central feature in this household. Sometimes my DC don't want to read the school-issued books because they'd prefer to read the books we've borrowed from the library, or one we've bought, or they've already read it at home/from library and don't want to do so again. I try to make an effort to fill in the diary so the teacher knows this, but if it's a busy week and I have 101 other things to do, it doesn't always get done. I would like to think from the comments I have made, my DCs level of ability, and my ongoing communication with the teacher that this is understood and not considered evidence that my child doesn't have anyone to read to.
YANBU about finding it sad that a child doesn't have parents who encourage reading, but I think it's a mistake to assume that this is because of lack of interest or to to assume that it has to take the form of reading a school-set book and writing comments in a reading diary.