I waited until you finished your article before commenting. It was well thought out, but it also ignores a lot of factors that went into the decision to sign Turner.
First off, Solano and Grichuk were signed long before the Bregman sweepstakes were completed. Grichuk is primarily an OF, and he just wasn't going to go to a team that already has 4 all star caliber OFers. Berti wasn't even signed until January 28th. So the earmarkings of what the infield was going to look like hadn't even taken shape yet. Signing a free agent has to be agreeable from both sides of the table.
The Cubs were still in the trade for a pitcher or sign Bregman mode, where improving the lineup was the first priority over a bat that can play 1b. If the Cubs did trade for Cease, it's possible that someone like Cronenworth or some other 1b capable bat could have been included in the deal to help the Padres with their financial struggles. Bregman would have made it where they may not have been able to afford a 1b bench bat. Basically, it would have been silly to put backup 1b as an option ahead of signing a Bregman or trading for Cease.
Now, once those guys are off the table and the appearance of spring deals is done, figuring out any gaping hole and filling it with the best of what's left makes a bit of sense. I'm not offended you used the term "freaking out" about not having a back up 1b or "pumped" about signing Justin Turner, but I will point out that this is not something I have seen, and seems to be stretching the truth like social media pages dramatize for "clicks".
You point out that the Berti signing was a great value and Justin Turner's is not. I think we can all agree with that. But sometimes you do have to overpay for things. A rookie player is amazing value if he is productive. Having several allows you to be able to overpay to improve the roster. The same can be said for late spring signings after you have exhausted all efforts to improve the team and you still have a wheelbarrow full of money to improve the end of the bench. Signing Turner does not stop the Cubs from adding pretty much whoever they want at the trade deadline, so in what way, shape or form does a Turner signing slow down this team in the big picture?
The bottom line is that Turner is likely a better bench bat than Lopez, Canario, Brujan and Workman, and we should probably include Kelly in that also for PH reasons. Those are the guys the front office should have been comparing Turner to, along with whoever was still a free agent like Canha or Grandal.
Finally, Turner is not stopping the Cubs from improving even if there was a significant injury. As you said yourself, there are plenty of guys that can be brought in to fill that void. What we don't want is another year of useless bench bats like Wisdom, Mastrobuoni, Madrigal and Mervis taking a significant percentage of the bench at bats. So, if you want to compare bench production at 1b, do so by comparing Turner's projected stats to Wisdom and Mervis from last year. I think we can all agree that he should be able to top those pretty easily.