Jordy, a prisoner can marry and many marriages have taken place inside prison.
The law cannot discriminate between heterosexual and same sex marriages.
If you can get past the sensationalist aspect of this story - the respective crimes committed and the apparent relationship between the two perpetrators, then you can be objective.
The punishment by law is incarceration – it does not include denial of rights offered to other prisoners.
So yes, they should be allowed to marry, however bizarre such a proposal may appear, it is still within their rights.
Blooming heck Jordy, do not call them scum on here otherwise you will be called by a few??? My views, well what can you say? you are dealing with the H.R.B. The " They have a rights brigade, you can not help but laugh at some of these clown brigades can you.