However it doesn't excuse people working on a web site funded by the taxpayer using it as a technology playground.
Where as developing stuff in house means that you're employing significantly cheaper labour (namely, the rubbish salaries that most get in the public sector vs the private sector) and as a bonus the cost is more likely going to stay within the UK (ie you're not paying multinational companies nor their overseas consultants (Oracle was particularly bad for this as they dumped our stuff in a US data centre and our support contacts were all living somewhere in eastern Europe. So very little - if anything - provided was UK based).
Sadly our government doesn't seem to understand about doing anything in between - or at least not that I observed when I used to work there. It was either entirely bespoke or entirely bought, developed and set up by some overpriced conglomerate (or worse yet, outsourced completely). So going by the trends that I've witnessed, I'd rather the technology playgrounds just so long as they remain developed in house.
Just because the organisation uses open-source software doesn't excuse them from public and professional scrutiny.
An MP spending £1645 on a duck house under expenses got a lot more attention than this little bit of waste. Just redressing the balance.