That may go to show he really committed the other bombings. But if he did commit those other bombings, that sufficiently explains his running and hiding. So it is not really very powerful evidence for the Olympic Park bombing.
How about the fact that this guy ran and hid for years?
With that logic they could pin the Laci Peterson and Jon Benet Ramsey case on him. Now he's claimed credit for the abortion and gay bar bombings. That is those are obviously connected to the same bomber if he and the bomber are one and the same. That bomber has never claimed credit for the Olympic Park bombings, and the motiviation as well as the type of bomb used doesn't fit.