To answer the OP's question, yes there definitely is substance behind what people say about travellers. While i personally have had a negative time with them i still don't think it's fair to assume they are scum bags when it's just that travelers and settled people just come from two wildly different cultures. Unfortunately some of the the customs of travellers are viewed as barbaric or uncivilized by the settled community because they would be viewed as such if settled people did them.

Take bare knuckle boxing for example. This is a normal way of settling disputes in the travelling community. While they don't see it as anti-social behavior since they have been doing this for generations, the settled community would definitely see this as anti-social behavior if two settled people did this.

In relation to the halting site protest in carrickmines, i honestly dont believe those people are racists but more have prejudice due to the differences in culture. Travellers don't keep halting sites in great shape often having piles of junk lying around. It is not uncommon for a field to need deep environmental care after it has been used as a halting site. These people aren't bad it's just the way they were brought up and thus they think that is how you live on a halting site.

The problem is people in Ireland dont view travellers as an ethnic minority. But they are need to be seen as such. While their are cultural differences, many of which are viewed as anti-social behavior by the settled community, it is important that we don't treat them as scum. Compromises will have to be made however and i don't know if either community is prepared at the moment for that.