Oracle database - query could bring database to a halt??

I come from a very strong technical background and can write sql queries in my sleep.  I have since switched over to more strategic and functional role and have experienced some of the hardest push back ever from a technology professional.  Most tech workers love me b/c I will write the code, hand it over and ask them to run anything that needs a function/procedure.  I'm very rare in doing this but I can do my job that much faster.  Since I started at my new position, I have had tremendous push back from technology.  There's a system in place that's a mess.  I was put in charge of trying to eliminate millions of duplicate records occuring each day.  Originally this number was around 6mm and now its closer to 12mm.  I somehow managed to get read-only access and technology nearly died almost demanding that I have my id revoked.  I was asked by my boss to run a query last night on another very large table.  Somehow during the nightly batch process, my id was put in queue and this morning caused the system to run at a terribly slow rate.  The tech staff obviously doesn't know what they are doing.  Originally, they told me there were only 400k records in the database but upon further investigation, I discovered millions and was immediately put on the defense while explaining how I got this number.  I noticed the database has nearly run out of space, certain reports do not run and I even suggested the cache needs to be increased.  After yesterday, the tech girl decided to email everyone under the sun with a screenshot that I don't know what I'm doing.  Granted its senior level staff that don't know anything about technology.  I've tried pointing out several items that make no sense:
1. several "fix" tables
2.. no archive process
3. no backup process
4. the list goes on and on

In the past I had to ask for a query for over 2 months and I received nothing.  Last week, someone from the business asked to update 5,000 records.  Technology told them this is a manual process -- for an Oracle database, I suggested a dataloader or something and they gave me eyes of death.  Now they want to revoke my access and belittle me.  Any advice on how to handle this??

My query was this:

select min (date) from holdings

-- that was it and I was told I didn't know what I was doing although she can't run a simple query and if she does the results are all incorrect.  I now have a meeting with my boss tomorrow and was told not to run any queries...I don't want to but I was asked to by my boss.  Anything I can do beforehand???