I think "actual hostility" would have been simply shutting Flickr off, something Yahoo was ready to do. (Post acquisition, they later publicly admitted they regretted not doing just that[1]). I'm surprised you view getting notices that you have the opportunity to download your content (or pay for it, your choice) to be hostile. Is it less hostile to simply delete the data with no warning, like hundreds of other services have done?
We've tried hard to thread the needle between fixing Flickr's business model (it was losing tens of millions of dollars a year when we bought them, primarily because giving away 1TB/account for free is not sustainable) and giving people plenty of time to download their photos prior to deletion.
Tough problem, tough situation, but I'm largely proud of how we've handled it - there's been plenty of runway and notice for people to get their photos back if they prefer not to pay (either scenario - paying or downloading - is fine in our minds, but losing photos is not). We're not holding them hostage or anything, we want everyone to have them, one way or the other.
Email open & click rates being what they are (low), we carefully tracked them, plus download and/or subscription rates, to determine how frequently to contact people so we could have a high confidence that most people knew they had a choice and had the chance to make it.
Your photos over the free limits will be deleted, eventually. I don't know when, for your specific account, but it's certainly not just to "silence empty threats". It's not a threat, it's a statement, and it was intended as a courtesy.
I'm glad you have a choice AND you _know_ you have a choice.
[1] https://www.wsj.com/articles/verizon-to-lay-off-7-of-media-g...