The obvious implication of such a statement (to me, at least) was that such a signing wouldn't have mattered in the slightest in the big picture. Similar comments are made when Lowe is criticized for allowing (Norris trophy candidate) Jan Hejda to walk away from the team as an unrestricted free agent, despite his willingness to sign.
Anyways, I would argue that all of those little decisions, for right or wrong, are very important. Case in point, Steve Staios- pictured above blocking a shot against the Red Wings. On July 12, 2001, the Oilers signed Staios to a three-year contract, after he was not extended a qualifying offer on his 525,000$ salary by the Atlanta Thrashers.
At the time, Staios was roving between defense and right wing, and was viewed as a tough guy with leadership (he'd been the Thrashers captain). Lowe had tried to acquire him at the draft, but Thrashers GM Don Waddell hadn't liked the offer, preferring to let him go for nothing. At the time, this signing really wasn't important.
Fast forward seven years. I personally will never forget Staios' gritty and determined performance in the 2006 Finals run. He's been a veteran, stabilizing presence on a blueline in need of it. He's certainly a core member of the team. And, it's important to remember, he came to the team in a signing that almost nobody noticed.
Think of the Curtis Glencross for Dick Tarnstrom trade earlier this year. I was fairly indifferent when I first heard of it, and as useful as Glencross looked, I didn't really think he'd have a major impact on the team. Now, his agent is pushing for a 2M/yr contract, after Glencross sparked Stortini and Brodziak into being one of the most dangerous 4th lines in the league down the stretch.
The list goes on. Tom Gilbert was a prospect acquired for imploding Tommy Salo 4 years ago. Patrick Thoreson was an unheralded undrafted UFA signing. Even Mathieu Garon wasn't expected to do much more than offer reliable backup goaltending.
Furthermore, when a team has obvious holes, say a lack of depth on RW, or a lack of veteran defensemen who can play against top opposition, signing a useful veteran with a good track record to fill the hole can have a huge impact on the team. Looking beyond Detroit's top line, how many players were brought in for a song and are playing significant roles? Cleary, Samuelsson, Draper, Lilja, Drake and McCarty at the very least.
All of the decisions made by GM's are important. Minor signings and trades can have a major impact on a roster, either when a player fills a needed hole, or when the player exceeds expectations. Those who pretend otherwise, those who think that every hole on the third or fourth line can be filled by a rookie, have little understanding of what it takes to win. Look at the rosters of contending teams. It shouldn't be a surprise that they generally have more than a couple of cagey, underrated veterans.