The problem the UK has is that it is a multicultural society and in many cultures, interaction between adults and children is legal, in their culture but their culture clashes with UK law because whilst the legal age for consent to sex is 16, and it is a criminal offence for anyone to be involved in a sexual act (sexual intercourse, sexual touching, kissing etc) with anyone under the age of 13 whether the young person agrees or not, on the basis that anyone under 13 lacks the capacity to give valid consent to any sexual act. There are cultures that legally allow sexual acts to take place with children under the age of 16 but as you can see, the UK has laws that prevent this so whilst someone may think they are behaving legally, whilst they are in the UK, what they are doing is actually illegal and as such the UK government has to protect children in the UK from all angles, culturally legal and criminal.
This wiki page shows the ages of sex consent of countries around the world and I think you'll be surprised at how young some of the ages are
https://en.wikipedia.org/wiki/Ages_of_consent_by_country
Yes people living and working in the UK need to abide by it's laws but you can see from the wiki page, if you have people from many of those countries who have been brought up with their own laws on age of consent and interaction with children, it can be difficult for them to adjust to the laws of the country they now reside in. I'm not making excuses for them but I can understand the difficulties. Hence why UK children need to be protected. Just because it was OK in their country does not mean it is OK in the UK.
Apple communication safety feature is a very good thing for the UK. I just hope UK parents take it onboard.