It's easy to find. I've gotten several calls after letters were printed. All they did was look me up in the phone book. How much easier is that now with the Internet?
I've received many calls after letters to the editor. I even had one county constable candidate come to my door twice to 'correct' my thinking.
This isn't the same as Doxxing. In a letter to the editor, you are choosing to release your name to the public.
In a Doxxing attack, the attacker is pulling up personal data on the poster who didn't choose that and is releasing that data for the purpose of harassment, intimidation, or worse.
For example, if you wrote a letter to the editor as Joe Smith, you chose to tell everyone you were Joe Smith and this is your belief.
However, if you signed your letter as 'Concerned Citizen' and someone digs up your personal data somehow and tells everyone that 'Concerned Citizen' is you and starts posting your name, number, employer, and other data, that's Doxxing. That in itself is illegal, however it becomes even more of a problem when it is done to harass, such as getting mobs of people on the internet to go after your employer to ruin your business reputation or get you fired.
Think about Yelp mobs ruining a business because they disagree with the owner's private political beliefs. That happens even when the owner expresses a belief anonymously now or has an anonymous account on a political forum (as an example).
Members of this and related forums are not unfamiliar with this. I don't know if you remember the old Clown Posse days where there was a big effort to 'out' freepers and post their personal information on line.
Even on this site, just last year, two members were banned for doxxing other members. In one case, a member started posting graphics with personal information of other members all over threads- information that those members didn't tell others on the forum.
Another member was banned for threatening the personal business of owner of this site. Threatening her he would 'out' her on Linked In and it 'would look bad for her business' if she opposed X.
These are very different cases than just signing a letter to the editor.