I think the issue is not about whether the Hadith do recommend punishment for apostates, it is quite clear that they do, but whether punishment for apostates is applicable in the current context. At the birth of Islam, the Prophet (peace be upon him) ruled a fragile city-state community that was at risk both from extrenal attack from the Makkans and their allies, but also from internal attack by the Jewish tribes and others who opposed the rule of the Prophet (peace be upon him). As said before, one attack of those who were trying to destroy Islam from the inside would be to enter Islam and then leave it, in order to lower Muslim moral, and breaking the goverment. So, in this context, execution of apostates would have been a necessary action to discourage this tresonous behaviour. In the Second World War, if a British citizen did a similar thing for similar reasons (obviously not false conversion to Christianity as this was not really an important factor), imprisonment or deportation would follow as a necessary action. And if Britain had actually been invaded, no doubt the punishment would be more severe.

The question is, was the commandment intended for these circumstances alone or for the whole of time? On one hand, there is no mention of the law being changed or removed in the hadith, but on the other hand, rules on for example war-captives and slavery are not corrected but are usually regarded today as being intended for Medieval Arabia rather than for all time.