Please delete this page
If you don't want to have your existing talk page to be indexed by web crawlers (like Google), you need to edit your talk page header yourself by adding the __NOINDEX__ keyword to it.
This will instruct web crawlers to NOT index this page, and (hopefully) remove it from their existing index.
I tried to do it for you, but it did not work: apparently MediaWiki only allows the User talk page owner to add that special keyword himself, otherwise it is not honored when saving (it does not alter the "page information" and so that keyword remains parsed as visible plain-text).
Try it: look at the rendered page (the keyword should be invisible and the "page information" should show that indexing is disabled. Then try looking in a few weeks at search engines to see if they effectively drop your user talk page from results from their search index, as instructed to them (give them time to revisit your talk page).
Note that individual "Thread:" pages managed by LiquidThread do not seem to automatically inherit that setting, so you may need to add the NOINDEX keyword in the top message of each thread you talked to, and that you don't want to be indexed by search engines. LiquidThread is not easy to manage, and in fact is now unmaintained. But this does not prohibit you to ask for deletions of thread pages and of your parent talk page, or "redacting" your edits top them in the page histories.
On some other Mediawikis, there are some authorized tools and Mediawiki extensions or privileged bots to automate it, where contents edited by others (and that must be kept) will be modified to "anonymize" your user name by using a randomly generated unique id instead, but I don't know if these tools work with LiquidThread pages, if they cannot "redact" the page histories.
But remember that when you started edited this wiki (or any other wiki), you accepted its open licence. So unless there are privacy issues strictly related to your personal data (just as your real name, email and street addresses, phone numbers and social network contacts) that is exclusively protected by law for you, all other contents your created or edited are available to anyone and that licence is irrevocable! So "redactions" will remain limited for legal reasons (related to the legal proof of ownership of the granted licence) all that can be done to the conserved content can only to be associated to an anomized unique identifier. Users should choose their public user names carefully if they are concerned by their privacy (this is not enough explained when creating an account on the wiki).
There are very few admins in this wiki (I'm not one of them, so I can just guide you and provide limited help or hints), and they don't have enough time to redact tons of pages (at least not without using some tools that they have been able to test) if many people ask for it, so be patient and consider your initial decision about usage terms and licencing that you accepted irrevocably.