IMO There is no blanket rule if it is right or wrong. Every child has to be assessed as an individual.
Do they get on well at school?
Can they catch up easy?
Will they gain by travelling instead of being in a classroom?
Do they have a lot of time of sick?
Just a few questions you need to ask yourself. End of the day do what you believe is right and not what anyone else tells you is right, only you know your child.
Personally we took DS out for 2 weeks every Oct at Junior school and 2 weeks in his 1st year at high school. This was in addition to other holidays within school holidays. Now he is 15 years old and been abroad 53 times (
list here) I believe 100% he would not be Head boy and aiming for about 14 GSCE's A-C grade if we had done things differently.
Travel to me is just as important as being in a classroom but there are many things to take into account. Thankfully we had full backing by head teachers, not as easy if you are at odds with the schools.