1) They found dna from an already living organism and used this as a blueprint
2) They (re)created this blueprint from scratch, all the while adding new strands that is effectively useless but are watermarks (names and such).
3) They then assembled this from scratch which is a really big deal, this isn't merely adding parts to an already existing strand this is creating the entire strand.
4) They then cleanesed another type of bacterium of its own dna
5) They inserted the dna, and then ordered it to activate. This too is very difficult
5) While the original "bacterium" may have cell parts that weren't created from the inserted dna, they then had the newly created bacterium create a billion copies of itself. While the original may not be fully synthetic the descendants are after a time fully synthetic.

So while the original may have been made somewhat from nature, the descendants definitely have man's image on them.