Why do people ruin things for others?

So currently in the process of building a house and it was nearly complete however people broke in and turned on all the water lines, blocked the sinks so the house would flood. Both floors were saturated with the second floor ceiling still dripping. Floors have been ripped out and plasterboard removed, I think a lot will need to be repaired / replaced. I am worried because if it's not replaced properly I am sure issues will come after such as mould. The second flooring foundation is saturated so much.

I am so disappointed that these people most likely did this for entertainment. They didn't steal anything, there wasn't much to steal but there were still some things. I would have an understanding of resorting to theft, for example stealing something to sell because you need money for living expenses. To not think of other's POV, have respect, know the difference between right and wrong etc. Neighbours had break in issues too and other neighbours heard stuff late at night and said they noticed a bunch of people, possibly youth.

I feel so sad that if it was youth, that they are doing these things. Their minds are elsewhere instead of spending time doing healthier things like placing their energy on dance, sport, making music etc. Sadly my area isn't that great, however I didn't feel it was this bad since I grew up here. Youth grouping up 6 vs 1 to steal someone's phone and also injure them. I saw during school holidays, kids were running through the trains and hiding in the drivers cabin, having to be caught and restrained by train staff.

Other areas offer much more for the youth to help support them so their minds are spent doing healthier things. Another could also be, that there aren't really consequences for youth who do these things. Here, they know security can't do anything so happily walk out stealing from the supermarket too. I know this topic can be quite deep as it could go into family dynamic, along with general support (government/community) but it is still so disappointing.

This was a long time coming, a lot of saving and sacrifice to have something destroyed. Something we have been working on since 2012, more actively since 2019. It is a waste of time, resources and effort by those who just wanted to get the job done.

Now I am worried about worse things happening like arson or animal poisoning.